Digital-Subband-Video-2

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As of June 20, 2025 the DSV2 bitstream is frozen (v2.8)

DSV2 is a lossy/lossless video codec using wavelets and block-based motion compensation. It performs best at medium-low to medium-high bitrates at resolutions between ~352x288 (CIF) to 1920x1080 (FHD). Comparable to MPEG-4 Part 2 and Part 10 (H.264) (P frames only) in terms of efficiency and quality.

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Example comparison (More can be found at the bottom of the README):

Stefan CIF minih264:

minih264_gop60.mp4

DSV2:

dsv2_gop60.mp4

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Note PDFs are out of date. They reflect the codec as it was when it was first uploaded here.

DSV2 Features (refer to PDF in repo for more detail)

• compression using multiresolution subband analysis instead of DCT
  • also known as a wavelet transform
• up to quarter-pixel motion compensation
• 4:1:0, 4:1:1, 4:2:0, 4:2:2 (+ UYVY) and 4:4:4 chroma subsampling formats
• adaptive quantization
• in-loop filtering
• lossless coding support
• intra and inter frames with variable length closed GOP
  • no bidirectional prediction (also known as B-frames). Only forward prediction with previous picture as reference

Improvements and New Features since DSV1

• in-loop filtering after motion compensation
• more adaptive quantization potential
• skip blocks for temporal stability
• new subband filters + support for adaptive subband filtering
• better motion compensation through Expanded Prediction Range Mode (EPRM)
• quarter pixel compensation
• lossless coding support
• psychovisual optimizations in the codec and encoder design

--- for more detailed information please refer to the informal specification document (DSV2_spec.pdf) in the repository.

Encoder Features (specific to this implementation of the DSV2 spec)

• single pass average bitrate (ABR) or constant rate factor (CRF) rate control
• more advanced Human Visual System (HVS) based intra block mode determination
• new Human Visual System (HVS) based intra frame adaptive quantization
• more complex scene change detection
• hierarchical motion estimation
• better temporal adaptive quantization
• written to be compatible with C89

--- for more detailed information please refer to the encoder information document (DSV2_encoder.pdf) in the repository.

Limitations

• no built-in interlacing support
• only 8 bits of depth per component supported
• frame sizes must be divisible by two

This code follows my self-imposed restrictions:

1. Everything must be done in software, no explicit usage of hardware acceleration.
2. No floating point types or literals, everything must be integer only.
3. No 3rd party libraries, only C standard library and OS libraries for window, input, etc.
4. No languages used besides C.
5. No compiler specific features and no SIMD.
6. Single threaded.

Compiling

C Compiler

All you need is a C compiler.

In the root directory of the project (with all the .h and .c files):

cc -O3 -o dsv2 *.c

Zig build system

If you have Zig installed, you can use the build.zig file to compile the project. Building requires Zig version ≥0.13.0.

0. Ensure you have Zig & git installed

1. Clone this repo & enter the cloned directory:

git clone https://github.com/LMP88959/Digital-Subband-Video-2
cd Digital-Subband-Video-2

2. Build the binary with Zig:

zig build

Note: If you'd like to specify a different build target from your host OS/architecture, simply supply the target flag. Example: zig build -Dtarget=x86_64-linux-gnu

3. Find the build binary in zig-out/bin. You can install it like so:

sudo cp zig-out/bin/dsv2 /usr/local/bin

Now, you should be all set to use the compiled dsv2 binary.

Running Encoder

Sample usage:

./dsv2 e -inp=video.y4m -out=compressed.dsv -y4m=1 -qp=60 -gop=48

Running Decoder

Sample usage:

./dsv2 d -inp=video.dsv -out=decompressed.y4m -y4m=1 -out420p=1

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NOTE: if -inp= and -out= are not specified, it will default to standard in / out (stdin/stdout). Only .yuv (one file containing all the frames) and .y4m files are supported as inputs to the encoder.

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Notes

This codec is by no means fully optimized, so there is a lot of room for performance gains. It performs quite well for what it is though.

Wavelet Codec Testbench

Check out this open source / work in progress wavelet codec testbench by Gianni Rosato!
https://github.com/gianni-rosato/wavelet-bench

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If you have any questions feel free to leave a comment on YouTube OR join the King's Crook Discord server :)

YouTube: https://www.youtube.com/@EMMIR_KC/videos

Discord: https://discord.gg/hdYctSmyQJ

itch.io: https://kingscrook.itch.io/kings-crook

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Example videos:

The H.264 file sizes were within a few kilobytes of their respective DSV2 file size.
H.264 examples were encoded using https://github.com/lieff/minih264 using -speed0 (best quality) unless otherwise stated
DSV2 examples were encoded with -effort=10 (best quality)

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Husky CIF - 29.97fps, GOP = 60 minih264:

h_minih264_gop60.mp4

DSV2:

h_dsv2_gop60.mp4

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Mobile CIF - 29.97fps, GOP = 60 minih264:

m_minih264_gop60.mp4

DSV2:

m_dsv2_gop60.mp4

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Parkrun 1280x720 - 50fps, GOP = 250

minih264:

p_minih264_gop250.mp4

x264 (encoded via ffmpeg with -c:v libx264 -preset superfast -crf 29.8 -refs 1 -coder vlc -bf 0 -g 250):

p_x264_gop250.mp4

DSV2: (Note this video here had to be re-encoded to fit under 10MB. I re-encoded with x264 CRF 22.5 with the veryslow preset)

p_dsv2_gop250.mp4