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39034f2bb5
ISM (Smooth Streaming) tracks raw-concatenate moof+mdat fragments with no ftyp/moov, so shaka-packager/mp4decrypt fail with PARSER_FAILURE (exit 2) on decrypt. The init box was previously built by n_m3u8dl_re, removed in the downloader consolidation. Add ism_init.py, a dependency-free byte-level MP4 init-segment synthesizer that rebuilds ftyp+moov from the manifest CodecPrivateData, ported from yt-dlp's write_piff_header and N_m3u8DL-RE's MSSMoovProcessor with full codec parity: - AVC (H264/AVC1/DAVC), with SPS/PPS picked by NAL type rather than position and NALUnitLengthField honored - HEVC (HVC1/HEV1) with chroma format and bit depths parsed from the de-emulated SPS via exp-Golomb so 10-bit/HDR signals correctly, and profile/tier/level lifted from the SPS PTL - Dolby Vision (DVHE/DVH1) as hvcC with a dvh1 sample entry - AAC (AACL/AACH) with the AudioSpecificConfig synthesized from SamplingRate/Channels when the manifest omits CodecPrivateData - EC-3 with a real dec3 box extracted from the WAVEFORMATEXTENSIBLE CodecPrivateData (Dolby GUID located by search, not fixed offset) - TTML subtitles as stpp/sthd/subt, wired for fragmented-TTML tracks CENC wrapping (encv/enca + sinf/tenc with default_KID) covers encrypted tracks: the per-sample IV size is derived from the fragment senc/saiz (PIFF override flag, payload arithmetic, saiz fallback) instead of assuming 8, and the constant-IV tenc form is supported. Read the track_ID from the first fragment's tfhd so the moov matches and the muxer does not drop samples. Wire ISM.download_track to prepend the synthesized init before merging; unsupported codecs soft-fail to raw concatenation with a warning. Harden against real-world inputs: 2-letter/uppercase manifest language tags normalize to ISO-639-2 (und fallback), >65535 Hz sample rates no longer overflow the 16.16 field, truncated tfhd returns None, struct.error joins the soft-fail handler, and the emulation-prevention scan no longer over-strips consecutive escapes. Add regression tests (37) covering box structure, every supported FourCC, 10-bit SPS parsing, ASC synthesis, dec3 extraction, IV-size derivation and the crash fixes. Validated structurally per codec with ffmpeg-minted fragments: shaka-packager parses synth-init+fragments with exit 0 and ffprobe reports the expected codec, including a live run against a public Smooth Streaming server.
unshackle
Movie, TV, and Music Archival Software
Install · Wiki · Docs · Discord
A modular archival tool for movies, TV, and music. Fork of Devine with DASH/HLS/ISM parsing, Widevine & PlayReady DRM, and a REST API.
Install
uv tool install git+https://github.com/unshackle-dl/unshackle.git
unshackle --help
Tip
Prefer
uv run unshackle ...inside a clone to keep the virtual environment active.
Requirements
External tools on your PATH (recommended versions):
- Python - 3.10 - 3.12
- uv - ≥ 0.5
- FFmpeg - ≥ 6.0
- MKVToolNix - ≥ 80
- shaka-packager - 2.6.1
- Bento4 - ≥ 1.6.0-639
- dovi_tool - ≥ 2.1
Optional:
- SubtitleEdit - ≥ 5.0 (
SeConvCLI)
License
GPL-3.0. Do not use unshackle for content you lack the rights to. Keep the core free and open; keep service code private. Be kind.