Dreamcast FMV Player

This is a proof-of-concept FMV (Full Motion Video) playback toolchain for the Sega Dreamcast. It includes:

• pack_dcmv: a frame+audio packer using lz4 HClevel 12 , or zstd level 13 compression
• fmv_play.elf: a Dreamcast player that decompresses and displays the video while streaming synced ADPCM audio
• conversion tools using ffmpeg + pvrtex + dcaconv

Goals

• Minimize CPU usage on Dreamcast by pre-processing all video/audio data
• Leverage hardware VQ-compressed textures and sound streaming for smooth playback

Project Structure

.
├── convert_to_pvr_fmv.sh       # Main conversion script (edit manually to configure input)
├── dcaconv                     # ADPCM encoder (built from TapamN's dcaconv repo)
├── pack_dcmv.c                 # Source for video+audio packer
├── pack_dcmv                   # Compiled binary (use: `gcc -O2 pack_dcmv.c -o pack_dcmv -llz4 -lzstd`)
├── generate_durations.py       # python3 script with PIL and ImageChops, numpy to find similiar png exported from ffmpeg and generate a repeat count of same frame to reduce size of dcmv file.
├── input/
│   └── Your source .mp4 files (manually configured in convert_to_pvr_fmv.sh)
├── playdcmv/
│   ├── fmv_play.c             # Dreamcast playback code (uses lz4, PVR, snd_stream)
│   ├── fmv_play.elf           # Compiled player binary
└── └── movie.dcmv             # Final Dreamcast FMV file

Dependencies

• ffmpeg: used to extract RGB64be png frames and audio from video files.
• pvrtex: builds VQ-compressed YUV422/RGB565 Dreamcast textures (from KOS utils folder)
• python3: python3 script with PIL and ImageChops, numpy to find similiar png exported from ffmpeg and generate a repeat count of same frame to reduce size of dcmv file.
• dcaconv: encodes WAV audio to Dreamcast ADPCM format (https://github.com/TapamN/dcaconv)
• lz4: used for lz4 compression [(https://github.com/GPF/lz4)](https://github.com/GPF/lz4) //for speed over size.
• zstd: used for zstd compression [(https://github.com/GPF/zstd)](https://github.com/GPF/zstd) //for size over speed.

Usage

1. Edit convert_to_pvr_fmv.sh:

   • Set the input video path (e.g., input/Dreamcast Startup (60fps).mp4) ([https://archive.org/details/dreamcaststartup60fps])
   • Adjust parameters like width, height, scalewidth, scaleheight, strided/pot texture size, FPS, compression type(lz4 or zstd),remove similiar frames, sample rate, channels, and audio bitrate

2. Run the script:

   ./convert_to_pvr_fmv.sh

3. Burn the resulting movie.dcmv + fmv_play.elf (or dcmv.cdi) to a disc or run with an emulator like Flycast or on real hardware.

License

This project is for educational/demo purposes. See individual tools for respective licenses.

Author

Troy E. Davis (@GPF) – Dreamcast homebrew hacker, QA engineer, and SDL3 port contributor.

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🎥 Screenshots and sample clips

output.mp4

📦 Header v6: YUV422 640x480 (content: 640x480) @ 23.97fps, 44100Hz, 2ch, unique=1039, total=1225 Frame size: 78848, Max compressed: 60789, Audio offset: 0x2B32AD6, Compression: LZ4 vid_set_mode: 640x480 VGA with 1 framebuffers. 🔄 Loading initial frames synchronously... ✅ Starting playback @ 41.72ms/frame, total=1225, unique=1039 🏁 Playback finished

arch: exit return code 0 arch: shutting down kernel vid_set_mode: 640x480 VGA with 1 framebuffers. gpf@GPF:/code/dreamcast/dreamcast-fmv/playdcmv$ ls -la movie.dcmv -rw-r--r-- 1 gpf gpf 47618230 Aug 22 20:33 movie.dcmv gpf@GPF:/code/dreamcast/dreamcast-fmv/playdcmv$

shrunk_10mb.mp4

IMG_1452.mov

pvrtexfmv_small.mp4

DirkSimple fmv video used with https://github.com/GPF/dirksimple port

cliffhangerDC.mp4

DragonsLairDC.mp4

Feel free to fork, test on hardware, or suggest features.