### Clone Repository and Setup

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This snippet shows how to clone the project repository and run the setup script. It requires Git and assumes the user has Docker installed, as the setup script likely prepares a Docker environment for subsequent commands.

```bash
git clone https://github.com/leandromoreira/digital_video_introduction.git
cd digital_video_introduction
./setup.sh
```

--------------------------------

### Setup Digital Video Project

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Clones the digital video introduction repository and runs the setup script. This is a prerequisite for performing hands-on exercises.

```Bash
git clone https://github.com/leandromoreira/digital_video_introduction.git
cd digital_video_introduction
./setup.sh
```

--------------------------------

### Start Jupyter Server

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This command initiates a Jupyter server, which is used for running interactive examples within the documentation. Users are instructed to copy the provided URL to access the server in their browser.

```bash
./s/start_jupyter.sh
```

--------------------------------

### FFmpeg Usage Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A link to a guide on how to use FFmpeg, potentially covering common use cases and avoiding pitfalls in video processing workflows.

```Shell
https://videoblerg.wordpress.com/2017/11/10/ffmpeg-and-how-to-use-it-wrong/
```

--------------------------------

### Start Jupyter Notebook with Docker

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This command initiates a Jupyter Notebook environment using Docker. Ensure Docker is installed before running this script. The script will guide you through the setup process via the console.

```bash
./s/start_jupyter.sh
```

--------------------------------

### H.264 Encoding Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A link to a guide on H.264 encoding, likely covering best practices and technical details for using the H.264/AVC video compression standard.

```Shell
http://www.adobe.com/devnet/adobe-media-server/articles/h264_encoding.html
```

--------------------------------

### VP9 Partitions Analysis Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Provides an example of analyzing VP9 video codec partitions, referencing a practical demonstration within a transcoding context. This analysis is typically performed using specialized tools like the Intel Video Pro Analyzer.

```URL
/encoding_pratical_examples.md#transcoding
```

--------------------------------

### Quantization Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This 'Do It Yourself' task demonstrates the effect of quantization, a lossy compression technique used in video codecs. Users will likely experiment with different quantization parameters to observe the trade-off between quality and size.

```bash
./s/ffmpeg -i input.mp4 -qp 28 output_quantized.mp4
```

--------------------------------

### Examine Partitions

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This 'Do It Yourself' section guides users to examine image partitions, a fundamental step in video codecs like H.264 and H.265. It helps understand how images are divided for more efficient compression.

```bash
./s/ffmpeg -i input.mp4 -vf "ldots=ldots" output_partitions.png
```

--------------------------------

### x264 Settings Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This guide from Wikibooks provides detailed information on x264 settings, a popular open-source encoder for H.264. It helps users optimize encoding parameters for different needs.

```Shell
https://en.wikibooks.org/wiki/MeGUI/x264_Settings
```

--------------------------------

### FFmpeg Wiki and Development

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

The FFmpeg wiki provides community-driven information, tutorials, and development resources. It's a great place to find specific guides and troubleshooting tips for using FFmpeg.

```Shell
https://trac.ffmpeg.org/wiki/
```

--------------------------------

### Video with Single I-Frame

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This 'Do It Yourself' example involves creating or analyzing a video that contains only a single I-frame (keyframe). This is useful for understanding intra-frame compression and its implications.

```bash
./s/ffmpeg -i input.mp4 -g 1 output_single_iframe.mp4
```

--------------------------------

### FFmpeg Oscilloscope Filter Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This entry refers to an example demonstrating the use of the FFmpeg oscilloscope filter. The specific command or code is not provided here, but it implies interaction with FFmpeg within a Docker container.

```bash
./s/ffmpeg -i input.mp4 -vf "ldots=..." output.mp4
```

--------------------------------

### Generate 2-Second Example Video with FFmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

Extracts a 2-second segment from a source video file, starting at a specific timestamp. This is useful for creating smaller test files or previews.

```shell
./s/ffmpeg -y -i /files/v/bunny_1080p_30fps.mp4 -ss 00:01:24 -t 00:00:02  /files/v/smallest_bunny_1080p_30fps.mp4
```

--------------------------------

### Variable-Length Coding (VLC) Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

This example demonstrates variable-length coding for symbols 'a', 'e', 'r', and 't' with given probabilities. It shows how to assign binary codes and compress a sequence of symbols, illustrating the concept of prefix codes.

```Python
# Symbol probabilities
probabilities = {'a': 0.3, 'e': 0.3, 'r': 0.2, 't': 0.2}

# Example binary codes (derived from Huffman or similar)
# Note: In a real implementation, these would be generated algorithmically.
vlc_codes = {
    'a': '0',
    'e': '10',
    'r': '110',
    't': '1110'
}

# Input sequence
input_sequence = "eat"

# Encode the sequence
encoded_bits = ""
for symbol in input_sequence:
    encoded_bits += vlc_codes[symbol]

print(f"Input sequence: {input_sequence}")
print(f"Encoded bits: {encoded_bits}")
print(f"Original bits (assuming 8 bits/symbol): {len(input_sequence) * 8}")
print(f"Compressed bits: {len(encoded_bits)}")

# Example of decoding (requires the same code table)
def decode_vlc(encoded_data, codes):
    reverse_codes = {v: k for k, v in codes.items()}
    decoded_sequence = ""
    current_code = ""
    for bit in encoded_data:
        current_code += bit
        if current_code in reverse_codes:
            decoded_sequence += reverse_codes[current_code]
            current_code = ""
    return decoded_sequence

decoded_sequence = decode_vlc(encoded_bits, vlc_codes)
print(f"Decoded sequence: {decoded_sequence}")

```

--------------------------------

### Android Media Formats Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Android developer documentation on media formats, covering supported audio and video codecs, containers, and playback capabilities on Android devices.

```Shell
https://developer.android.com/guide/topics/media/media-formats.html
```

--------------------------------

### Transcode Video to VP9 with FFmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

Transcodes a video file to the VP9 codec with a specified bitrate, using the libvpx-vp9 encoder and libvorbis for audio. This example demonstrates efficient video compression.

```shell
./s/ffmpeg -i /files/v/smallest_bunny_1080p_30fps.mp4 -c:v libvpx-vp9 -b:v 600K -c:a libvorbis /files/v/smallest_bunny_1080p_30fps_vp9.webm
```

--------------------------------

### FFmpeg Rate Control Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A guide to rate control in FFmpeg, explaining different methods like Constant Rate Factor (CRF) and Variable Bitrate (VBR) for managing video quality and file size.

```Shell
http://slhck.info/video/2017/03/01/rate-control.html
```

```Shell
http://slhck.info/video/2017/02/24/vbr-settings.html
```

```Shell
http://slhck.info/video/2017/02/24/crf-guide.html
```

--------------------------------

### H.264 Encoding Guide

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This article from Adobe discusses H.264 encoding, providing insights into the process and best practices for achieving efficient video compression.

```Shell
http://www.adobe.com/devnet/adobe-media-server/articles/h264_encoding.html
```

--------------------------------

### Uniform Quantization Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

Illustrates the process of uniform quantization by dividing a coefficient block by a scalar value (e.g., 10) and rounding. It also shows the reverse process (de-quantization) by multiplying by the same scalar.

```Python
import numpy as np

# Assume coefficient_block is the result from DCT
# For demonstration, let's create a sample block
coefficient_block = np.random.randint(-100, 100, size=(8, 8))

quantization_step = 10

# Quantization
quantized_block = np.round(coefficient_block / quantization_step)

print("Original Coefficient Block:\n", coefficient_block)
print("\nQuantized Block:\n", quantized_block)

# De-quantization (Re-quantization)
reconstructed_coefficients = quantized_block * quantization_step

print("\nDe-quantized Coefficients:\n", reconstructed_coefficients)

```

--------------------------------

### FFmpeg Command-Line Tool

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

FFmpeg is a powerful open-source tool for handling multimedia data. It can be used for recording, converting, and streaming audio and video. The provided links offer comprehensive documentation and usage examples.

```Shell
https://ffmpeg.org/
```

```Shell
https://ffmpeg.org/ffmpeg-all.html
```

```Shell
https://ffmpeg.org/ffprobe.html
```

--------------------------------

### Variable-Length Coding (VLC) Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Demonstrates Variable-Length Coding (VLC) for symbol compression. Symbols with higher probabilities are assigned shorter binary codes, and vice versa. The example shows encoding the stream 'eat' using predefined codes, resulting in a compressed bitstream.

```text
Symbol Table:
  a: probability 0.3, binary code 0
  e: probability 0.3, binary code 10
  r: probability 0.2, binary code 110
  t: probability 0.2, binary code 1110

Stream 'eat' encoded: [10][0][1110] -> 1001110 (7 bits)
```

--------------------------------

### Start Jupyter with Docker

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

This command initiates a Jupyter Notebook environment using Docker. It assumes a script named 'start_jupyter.sh' is available in the './s/' directory. Users should follow the terminal instructions after execution.

```bash
./s/start_jupyter.sh
```

--------------------------------

### Quantization Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Illustrates a simple uniform quantization process where a block of coefficients is divided by a single value (e.g., 10) and then rounded. The reverse process, re-quantization, involves multiplying by the same value.

```text
Quantize block: divide by 10, round.
Re-quantize block: multiply by 10.
```

--------------------------------

### Variable Length Coding (VLC) Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

Demonstrates Variable Length Coding (VLC) using a simple probability table for symbols 'a', 'e', 'r', 't'. It shows how assigning shorter binary codes to more frequent symbols can achieve compression.

```Python
# Example symbol probabilities
probabilities = {'a': 0.3, 'e': 0.3, 'r': 0.2, 't': 0.2}

# Example VLC codes (manually assigned for demonstration)
# In practice, Huffman coding or similar algorithms generate these.
vlc_codes = {
    'a': '0',
    'e': '10',
    'r': '110',
    't': '1110'
}

# Input stream to compress
input_stream = "eat"

# Encode the stream
encoded_stream = "".join([vlc_codes[char] for char in input_stream])

print(f"Input stream: {input_stream}")
print(f"VLC Codes: {vlc_codes}")
print(f"Encoded stream (bits): {encoded_stream}")

# Calculate original and compressed size (assuming 8 bits per char originally)
original_size_bits = len(input_stream) * 8
compressed_size_bits = len(encoded_stream)

print(f"Original size: {original_size_bits} bits")
print(f"Compressed size: {compressed_size_bits} bits")
print(f"Compression ratio: {original_size_bits / compressed_size_bits:.2f}x")

# Decoding requires the same VLC table
def decode_stream(encoded_data, codes):
    reverse_codes = {v: k for k, v in codes.items()}
    decoded_text = ""
    current_code = ""
    for bit in encoded_data:
        current_code += bit
        if current_code in reverse_codes:
            decoded_text += reverse_codes[current_code]
            current_code = ""
    return decoded_text

decoded_text = decode_stream(encoded_stream, vlc_codes)
print(f"Decoded stream: {decoded_text}")

```

--------------------------------

### DCT Transformation Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

Demonstrates the transformation of a pixel block into frequency coefficients using DCT. It shows the resulting coefficient block and its visual representation, emphasizing the concentration of energy in low-frequency components.

```Python
import numpy as np

def dct2(a):
    return np.fft.fft2(a)

# Example pixel block (8x8)
pixel_block = np.random.rand(8, 8) * 255

# Apply DCT
coefficient_block = dct2(pixel_block)

# Displaying the coefficient block (for demonstration, actual visualization would be different)
print("DCT Coefficient Block:\n", coefficient_block)

# To visualize, one might take the magnitude and log scale
import matplotlib.pyplot as plt

plt.figure()
plt.imshow(np.log(np.abs(coefficient_block) + 1e-9), cmap='gray')
plt.title('DCT Coefficients (Log Scale)')
plt.colorbar()
plt.show()

# Example of zeroing out high-frequency coefficients (e.g., bottom-right)
quantized_block = coefficient_block.copy()
quantized_block[4:, 4:] = 0 # Zero out a portion

# Inverse DCT (for demonstration of reversibility)
from scipy.fftpack import idctn

reconstructed_block = idctn(quantized_block, shape=pixel_block.shape)

plt.figure()
plt.subplot(1, 2, 1)
plt.imshow(pixel_block, cmap='gray')
plt.title('Original Pixel Block')

plt.subplot(1, 2, 2)
plt.imshow(reconstructed_block, cmap='gray')
plt.title('Reconstructed Block')
plt.show()

```

--------------------------------

### FFmpeg Macroblocks and Motion Vectors Debugging

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A guide on debugging macroblocks and motion vectors in FFmpeg, providing insights into how to analyze video frames and motion estimation for troubleshooting encoding issues.

```Shell
https://trac.ffmpeg.org/wiki/Debug/MacroblocksAndMotionVectors
```

--------------------------------

### Inspect Video Properties with FFmpeg/mediainfo

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

This snippet provides a link to a practical guide on using FFmpeg or mediainfo to inspect various video properties discussed in the document, such as resolution, frame rate, and encoding type (CBR/VBR). It's a hands-on approach to understanding video characteristics.

```text
You can [check most of the  explained properties with ffmpeg or mediainfo.](https://github.com/leandromoreira/introduction_video_technology/blob/master/encoding_pratical_examples.md#inspect-stream)
```

--------------------------------

### Generate H.264 Bitstream with ffmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

This command uses ffmpeg to convert a PNG image into a raw H.264 bitstream. The output stream will have a yuv420 color space and a single frame of 64x64 resolution. This is a practical example of creating a basic video bitstream.

```bash
./s/ffmpeg -i /files/i/minimal.png -pix_fmt yuv420p /files/v/minimal_yuv420.h264
```

--------------------------------

### Streaming Onboarding Material

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Onboarding material for streaming technologies, likely covering introductory concepts and best practices for setting up and managing video streaming services.

```Shell
https://github.com/Eyevinn/streaming-onboarding
```

--------------------------------

### JPEG Quantization Matrix Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

This snippet provides an example of a quantization matrix used in JPEG compression. It highlights how different coefficients are quantized differently, with more emphasis on lower-left coefficients and less on upper-right ones.

```C++
#include <iostream>
#include <vector>

// Example quantization matrix (simplified)
const std::vector<std::vector<int>> quantization_matrix = {
    {16, 11, 10, 16, 24, 40, 51, 61},
    {12, 12, 14, 19, 26, 29, 35, 41},
    {14, 13, 16, 24, 30, 34, 42, 47},
    {14, 17, 21, 26, 31, 37, 44, 51},
    {18, 22, 27, 32, 37, 43, 50, 56},
    {20, 25, 30, 36, 42, 48, 55, 62},
    {24, 29, 34, 40, 47, 54, 61, 68},
    {28, 33, 39, 45, 52, 59, 66, 75}
};

int main() {
    // In a real scenario, this matrix would be used to divide DCT coefficients.
    // For example:
    // quantized_coefficient = round(original_coefficient / quantization_matrix[row][col]);
    std::cout << "Example quantization matrix loaded." << std::endl;
    return 0;
}
```

--------------------------------

### Online Courses and Tutorials

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This section provides links to various online courses and tutorials covering digital video, compression, and related technologies.

```Shell
https://www.coursera.org/learn/digital/
```

```Shell
https://people.xiph.org/~tterribe/pubs/lca2012/auckland/intro_to_video1.pdf
```

```Shell
https://xiph.org/video/vid1.shtml
```

```Shell
https://xiph.org/video/vid2.shtml
```

--------------------------------

### libvpx VP9 Source Code

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Link to the libvpx repository on GitHub, specifically the VP9 codec implementation, allowing developers to access and study the source code.

```Shell
https://github.com/webmproject/libvpx/tree/master/vp9
```

--------------------------------

### H.264 Encoding Explained

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This resource likely explains the process of H.264 encoding, potentially covering parameters and best practices.

```Shell
http://www.lighterra.com/papers/videoencodingh264/
```

--------------------------------

### WebM Project Resources

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link points to the Google Code repository for libvpx, the open-source software implementation of the VP8 and VP9 video codecs.

```Shell
https://github.com/webmproject/libvpx/tree/master/vp9
```

--------------------------------

### Video Sequences for Testing

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link provides access to video datasets and organizations involved in video quality testing and benchmarking.

```Shell
http://bbb3d.renderfarming.net/download.html
```

```Shell
https://www.its.bldrdoc.gov/vqeg/video-datasets-and-organizations.aspx
```

--------------------------------

### FFmpeg Wiki

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

The official FFmpeg wiki, containing a wealth of information, tutorials, and community contributions related to FFmpeg usage and development.

```Shell
https://trac.ffmpeg.org/wiki/
```

--------------------------------

### How Video Works

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A resource explaining the fundamental principles of how video works, from capture to display, covering concepts like frame rates, resolution, and encoding.

```Shell
https://howvideo.works/
```

--------------------------------

### 使用 FFmpeg 生成包含帧间预测（运动向量）的视频

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

演示如何使用 FFmpeg 工具生成包含帧间预测（运动向量）信息的调试视频，以便直观地分析视频压缩过程中的运动估计。

```bash
ffmpeg -i input.mp4 -vf "idet,schedts,showinfo,drawtext=text='Frame %d':x=10:y=10:fontsize=24:fontcolor=white" -f null -
```

--------------------------------

### H.264 Resolution Calculation Fields

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Shows example parameters from an SPS NAL unit used to calculate video resolution: `pic_width_in_mbs_minus_1` and `pic_height_in_map_units_minus_1`. These values are encoded using Exp-Golomb coding.

```text
pic_width_in_mbs_minus_1
```

```text
pic_height_in_map_units_minus_1
```

--------------------------------

### Check Video Properties with mediainfo

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This 'Do It Yourself' section involves checking video properties using the 'mediainfo' tool, likely executed within a Docker container as indicated by the './s/mediainfo' prefix. This helps users understand video file characteristics.

```bash
./s/mediainfo video.mp4
```

--------------------------------

### FOSDEM AV1 Presentation

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link refers to a presentation about AV1 at FOSDEM, likely covering its development and features.

```Shell
https://fosdem.org/2017/schedule/event/om_av1/
```

--------------------------------

### MP3 and AAC Explained

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This resource provides an explanation of MP3 and AAC audio compression formats, covering their principles and how they work.

```Shell
https://prezi.com/8m7thtvl4ywr/mp3-and-aac-explained/
```

--------------------------------

### 使用 FFmpeg 生成包含宏块及帧内预测的视频

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

展示如何利用 FFmpeg 工具生成包含宏块和帧内预测信息的视频，这有助于理解帧内预测的原理以及宏块的颜色编码含义。

```bash
ffmpeg -i input.mp4 -vf "idet,schedts,showinfo,drawtext=text='Frame %d':x=10:y=10:fontsize=24:fontcolor=white" -f null -
```

--------------------------------

### H.264 IDR Slice NAL Unit Type

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

An IDR (Instantaneous Decoding Refresh) slice NAL unit signifies the start of an intra-coded picture. Its NAL unit type is typically represented as `00101` (decimal 5).

```text
Example IDR Slice NAL unit first byte (after sync marker):
Binary representation of first 6 bytes: 01100101 10001000 10000100 00000000 00100001 11111111
NAL Unit Type (last 5 bits of first byte): 00101 (Decimal 5), indicating IDR Slice.
```

--------------------------------

### Introduction to Video Compression

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This presentation offers an introduction to the fundamental concepts of video compression.

```Shell
http://www.slideshare.net/vcodex/introduction-to-video-compression-13394338
```

--------------------------------

### Get RGB Pixel Intensity

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/image_as_3d_array.ipynb

Retrieves the RGB intensity values of a specific pixel from a processed image region. It then prints the Red, Green, and Blue intensity, scaled to a 0-255 range.

```python
latest_pixel = zoomed_eye_split[3, 3]
print("R intensity at x=3, y=3 is",round(256 * latest_pixel[0]))
print("G intensity at x=3, y=3 is",round(256 * latest_pixel[1]))
print("B intensity at x=3, y=3 is",round(256 * latest_pixel[2]))
```

--------------------------------

### VP9 Video Codec Overview

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

An overview of the VP9 video codec, discussing its features and how it works, providing insights into this efficient video compression standard.

```Shell
https://blogs.gnome.org/rbultje/2016/12/13/overview-of-the-vp9-video-codec/
```

--------------------------------

### H.264 SPS NAL Unit Profile IDC

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

The second byte of an H.264 SPS NAL unit specifies the `profile_idc`, which indicates the encoding profile used. For example, a `profile_idc` value might correspond to profiles like 'Constrained High'.

```text
Example SPS NAL unit second byte:
- Binary: 01100100
- Hexadecimal: 0x64
- Decimal: 100
- Corresponds to 'Constrained High' profile.
```

--------------------------------

### Audio Compression Explained

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This presentation explains the principles behind audio compression, likely covering formats like MP3 and AAC.

```Shell
http://www.slideshare.net/MadhawaKasun/audio-compression-23398426
```

--------------------------------

### Generate Debug Video with ffmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

This example demonstrates how to generate a video that visualizes macro-blocks and their predictions using ffmpeg. It's useful for understanding intra-frame prediction techniques in detail. Refer to the ffmpeg documentation for a deeper understanding of macro-block types.

```bash
ffmpeg -i input.mp4 -vf "codecview=mv=0:inter=0" -c:a copy output.mp4
```

--------------------------------

### Exponential-Golomb Decoding Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

Exponential-Golomb coding is used to decode variable-length values in H.264, such as 'ue(v)', 'me(v)', 'se(v)', and 'te(v)'. This method is efficient for encoding values with many defaults.

```text
ue(v)
```

```text
me(v)
```

```text
se(v)
```

```text
te(v)
```

--------------------------------

### H.264 SPS NAL Unit Profile IDC

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

The second bit of the first byte in an SPS NAL unit represents the profile_idc. In the example `01100100` (binary), the profile_idc is `01100` (binary), which corresponds to a high profile.

```binary
01100100
```

--------------------------------

### Doom9 Forum Discussions

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Links to discussions on the Doom9 forum, a popular community for video encoding enthusiasts, covering topics related to codecs and video processing.

```Shell
https://forum.doom9.org/showthread.php?t=167081
```

```Shell
https://forum.doom9.org/showthread.php?t=168947
```

--------------------------------

### FFmpeg and FFprobe Usage

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Links to the official FFmpeg and FFprobe documentation, essential command-line tools for handling multimedia data. These tools are widely used for video and audio conversion, streaming, and analysis.

```Shell
https://ffmpeg.org/
```

```Shell
https://ffmpeg.org/ffmpeg-all.html
```

```Shell
https://ffmpeg.org/ffprobe.html
```

--------------------------------

### MP3 and AAC Explained

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

An explanation of MP3 and AAC audio compression formats, covering their principles, features, and differences.

```Shell
https://prezi.com/8m7thtvl4ywr/mp3-and-aac-explained/
```

--------------------------------

### H.264 IDR Slice NAL Unit Header Example

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Provides the first 6 bytes of an IDR Slice NAL unit, illustrating the binary values that define its type and header information. The `nal_unit_type` for an IDR slice is 5.

```binary
01100101 10001000 10000100 00000000 00100001 11111111
```

--------------------------------

### Video Encoding Course

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link suggests an online course focused on video encoding, likely covering various codecs and techniques.

```Shell
http://slhck.info/ffmpeg-encoding-course
```

--------------------------------

### Parse H.264 Bitstream with MediaInfo Source Code

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

This snippet provides a link to the C++ source code for parsing H.264 (AVC) bitstreams, as used by the MediaInfo tool. It's a practical example for understanding how bitstream data is processed programmatically.

```cpp
https://github.com/MediaArea/MediaInfoLib/blob/master/Source/MediaInfo/Video/File_Avc.cpp
```

--------------------------------

### VP9 Video Codec Overview

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This blog post offers an overview of the VP9 video codec, discussing its features and advantages as an open and royalty-free compression standard.

```Shell
https://blogs.gnome.org/rbultje/2016/12/13/overview-of-the-vp9-video-codec/
```

--------------------------------

### H.264 NAL Unit Type Identification

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

The first bit of a NAL unit is the forbidden_zero_bit, followed by two bits for nal_ref_idc, and the remaining five bits indicate the nal_unit_type. For example, a nal_unit_type of '00111' (binary) signifies an SPS NAL unit (type 7).

```binary
01100111
```

--------------------------------

### CABAC vs CAVLC

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-cn.md

This section provides a practical comparison between CABAC (Context-Adaptive Binary Arithmetic Coding) and CAVLC (Context-Adaptive Variable-Length Coding), two entropy coding methods used in video compression. The examples likely involve encoding the same content with both methods.

```bash
./s/ffmpeg -i input.mp4 -coder cabac output_cabac.mp4
./s/ffmpeg -i input.mp4 -coder cavlc output_cavlc.mp4
```

--------------------------------

### H.264 Bitstream Exploration

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This series of posts delves into the H.264 bitstream, breaking down its structure and explaining various components like NAL units.

```Shell
http://gentlelogic.blogspot.com.br/2011/11/exploring-h264-part-2-h264-bitstream.html
```

```Shell
http://yumichan.net/video-processing/video-compression/introduction-to-h264-nal-unit/
```

--------------------------------

### Generazione di un video a fotogramma singolo

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

Questo snippet descrive il processo di generazione di un video composto da un singolo fotogramma, utile per testare e analizzare i codec video. Viene fatto riferimento a un esempio pratico per la creazione di tale video.

```bash
ffmpeg -f lavfi -i color=c=red:s=1280x720:r=30 -frames:v 1 -c:v libx264 -pix_fmt yuv420p single_frame.mp4
```

--------------------------------

### Digital Cameras Explained

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This article explains the fundamental principles behind digital cameras, including how they capture images and video.

```Shell
http://www.explainthatstuff.com/digitalcameras.html
```

--------------------------------

### H.264 Bitstream Exploration

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A blog post series exploring the H.264 bitstream, offering a deep dive into the structure and details of the H.264 video format.

```Shell
http://gentlelogic.blogspot.com.br/2011/11/exploring-h264-part-2-h264-bitstream.html
```

--------------------------------

### Video Encoding and Compression Books

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This section lists several books related to video encoding and compression, covering topics from general principles to specific standards like H.264.

```Shell
https://www.amazon.com/Understanding-Compression-Data-Modern-Developers/dp/1491961538/ref=sr_1_1?s=books&ie=UTF8&qid=1486395327&sr=1-1
```

```Shell
https://www.amazon.com/H-264-Advanced-Video-Compression-Standard/dp/0470516925
```

```Shell
https://www.amazon.com/Practical-Guide-Video-Audio-Compression/dp/0240806301/ref=sr_1_3?s=books&ie=UTF8&qid=1486396914&sr=1-3&keywords=A+PRACTICAL+GUIDE+TO+VIDEO+AUDIO
```

```Shell
https://www.amazon.com/Video-Encoding-Numbers-Eliminate-Guesswork/dp/0998453005/ref=sr_1_1?s=books&ie=UTF8&qid=1486396940&sr=1-1&keywords=jan+ozer
```

--------------------------------

### Introduction to Video Compression

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A presentation providing an introduction to video compression, explaining the fundamental principles and techniques used to reduce video data size.

```Shell
http://www.slideshare.net/vcodex/introduction-to-video-compression-13394338
```

--------------------------------

### Open Source Codecs

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link points to the Google Source repository for the Alliance for Open Media, likely containing information and code for AV1 and other open codecs.

```Shell
https://aomedia.googlesource.com/
```

--------------------------------

### Stack Overflow - Understanding H.264

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This Stack Overflow question aims to help users understand the H.264 video codec, likely covering its structure and encoding principles.

```Shell
http://stackoverflow.com/a/24890903
```

--------------------------------

### Digital Camera Explanation

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

An explanation of how digital cameras work, covering aspects like image sensors, optics, and the process of capturing digital images.

```Shell
http://www.explainthatstuff.com/digitalcameras.html
```

--------------------------------

### Video Encoding and H.264

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This resource likely provides information on video encoding, with a specific focus on the H.264 standard.

```Shell
http://www.hkvstar.com
```

```Shell
http://www.hometheatersound.com/
```

--------------------------------

### Audio Compression Explanation

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A presentation explaining audio compression techniques, likely covering concepts like MP3 and AAC and how they reduce audio file sizes.

```Shell
http://www.slideshare.net/MadhawaKasun/audio-compression-23398426
```

--------------------------------

### Video Compression Concepts

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This link provides a PDF document that likely covers various concepts related to video compression standards and techniques.

```Shell
http://www.springer.com/cda/content/document/cda_downloaddocument/9783642147029-c1.pdf
```

--------------------------------

### x264 and x265 Comparison

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A Netflix tech blog post comparing x264 and x265, two popular software implementations of H.264 and HEVC video codecs, respectively, focusing on their performance and quality.

```Shell
http://techblog.netflix.com/2016/08/a-large-scale-comparison-of-x264-x265.html
```

--------------------------------

### Transcode Video with FFmpeg (H.264 to H.265)

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

Transcode a video file from H.264 codec to H.265 codec using FFmpeg.

```bash
./s/ffmpeg -i /files/v/small_bunny_1080p_30fps.mp4 -c:v libx265 /files/v/small_bunny_1080p_30fps_h265.mp4
```

--------------------------------

### DCT Transform Experience

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Allows users to interactively apply the DCT transform to images, experiment with discarding coefficients, and observe the reconstruction process. This hands-on experience helps in understanding the practical application of DCT for image compression.

```Python
from uniform_quantization_experience import DCTExperience

# Initialize and run the DCT experience
experience = DCTExperience()
experience.run()

```

--------------------------------

### H.264 vs HEVC Comparison

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A presentation comparing H.264 and HEVC video codecs, highlighting their differences in compression efficiency and features.

```Shell
http://www.slideshare.net/mwalendo/h264vs-hevc
```

--------------------------------

### H.264 Encoding Concepts

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A resource explaining H.264 encoding, likely covering the underlying principles and parameters involved in achieving efficient video compression.

```Shell
http://www.lighterra.com/papers/videoencodingh264/
```

--------------------------------

### Generate Debug Video with FFmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

Demonstrates how to generate a video visualizing inter prediction and motion vectors using the FFmpeg command-line tool. This is useful for debugging and understanding motion estimation in video encoding.

```bash
ffmpeg -i input.mp4 -vf "drawmotionvectors=mode=0:path=path.txt" output.mp4
```

--------------------------------

### Generate Video from Sequence of Simple Images (White Background)

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

This command creates a video from a sequence of PNG images that have a white background. The `%d` in the input filename pattern handles sequentially numbered images.

```bash
./s/ffmpeg -i /files/i/solid_background_ball_%d.png -pix_fmt yuv420p /files/v/solid_background_ball_yuv420.mp4
```

--------------------------------

### H.264 Encoding Comparison

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This PDF document presents a comparison of various H.264 video codecs, evaluating their performance and compression efficiency.

```Shell
http://www.compression.ru/video/codec_comparison/h264_2012/mpeg4_avc_h264_video_codecs_comparison.pdf
```

--------------------------------

### Video Compression PDF

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This PDF document likely delves into the technical aspects of video compression, potentially covering algorithms and standards.

```Shell
https://arxiv.org/pdf/1702.00817v1.pdf
```

--------------------------------

### Transcode Video with FFmpeg (H.264 to VP9/Vorbis)

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

Transcode a video file from H.264 codec to VP9 video codec and Vorbis audio codec, outputting to a WebM container.

```bash
./s/ffmpeg -i /files/v/small_bunny_1080p_30fps.mp4 -c:v libvpx-vp9 -c:a libvorbis /files/v/small_bunny_1080p_30fps_vp9.webm
```

--------------------------------

### Generate Video from Sequence of Images (With Background)

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

This command creates a video from a sequence of PNG images that include a background. The `%d` in the input filename pattern handles sequentially numbered images.

```bash
./s/ffmpeg -i /files/i/smw_background_ball_%d.png -pix_fmt yuv420p /files/v/smw_background_ball_yuv420.mp4
```

--------------------------------

### Daala Video Codec Demo

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A link to a demo of the Daala video codec, an open-source, royalty-free codec developed by Xiph.Org Foundation, showcasing its capabilities.

```Shell
https://ghostarchive.org/archive/0W0d8
```

--------------------------------

### Esercitazione su immagini e colori con Jupyter

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-it.md

Questo snippet fornisce un link a un notebook Jupyter per sperimentare con immagini e colori utilizzando librerie Python come NumPy e Matplotlib. È utile per comprendere le rappresentazioni delle immagini e le manipolazioni dei colori.

```Python
import numpy as np
import matplotlib.pyplot as plt

# Esempio di caricamento e visualizzazione di un'immagine (richiede un file immagine)
# img = plt.imread('nome_file_immagine.png')
# plt.imshow(img)
# plt.title('Immagine Caricata')
# plt.show()

# Esempio di creazione di una matrice di colore RGB
# red_channel = np.zeros((100, 100), dtype=np.uint8)
# green_channel = np.full((100, 100), 255, dtype=np.uint8)
# blue_channel = np.zeros((100, 100), dtype=np.uint8)
# 
# rgb_image = np.stack((red_channel, green_channel, blue_channel), axis=-1)
# plt.imshow(rgb_image)
# plt.title('Immagine Verde')
# plt.show()

```

--------------------------------

### ITU-T Recommendations Index

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A link to the ITU-T recommendations index, allowing users to browse and access various telecommunication standards, including those related to video and audio.

```Shell
http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=12904&lang=en
```

--------------------------------

### Run VMAF Comparison with FFmpeg and VMAF Tool

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/encoding_pratical_examples.md

Executes a VMAF (Video Multimethod Assessment Fusion) analysis to compare the perceptual quality of an original video against a transcoded version. It takes the raw YUV data of both videos as input and outputs the results in JSON format.

```shell
./s/vmaf run_vmaf yuv420p 1080 720 /files/v/smallest_bunny_1080p_30fps.yuv /files/v/smallest_bunny_1080p_30fps_vp9.yuv --out-fmt json
```

--------------------------------

### MediaInfo Tool

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

A link to MediaInfo, a convenient cross-platform tool that displays technical and tag information for video and audio files. It's useful for analyzing media file properties.

```Shell
https://mediaarea.net/en/MediaInfo
```

--------------------------------

### x264 vs x265 Comparison

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README-ko.md

This Netflix tech blog post compares the performance and quality of x264 and x265 encoders, providing insights into the trade-offs between H.264 and HEVC compression.

```Shell
http://techblog.netflix.com/2016/08/a-large-scale-comparison-of-x264-x265.html
```

--------------------------------

### Generate Debug Video with FFmpeg

Source: https://github.com/leandromoreira/digital_video_introduction/blob/master/README.md

This snippet provides a link to generate a video demonstrating macro blocks and their predictions using FFmpeg. It also links to FFmpeg documentation for understanding macroblock types.

```markdown
You can [generate a video with macro blocks and their predictions with ffmpeg.](/encoding_pratical_examples.md#generate-debug-video) Please check the ffmpeg documentation to understand the [meaning of each block color](https://trac.ffmpeg.org/wiki/Debug/MacroblocksAndMotionVectors?version=7#AnalyzingMacroblockTypes).
```