UNITY_MATRIX emitted 11 int32s instead of 9, oversizing mvhd/tkhd so pymp4 desynced and fTTML subtitles yielded no cues. Also rewrites PIFF senc to CENC so shaka can decrypt Smooth, labels HEV1 as hev1, and raises when a fragment survives decryption still carrying a sample-encryption box.
Smooth fragments set tfhd sample_description_index=2 against a server init carrying a second, identical sample entry. A lone entry left that dangling: mp4decrypt skipped every such fragment silently and demuxers stopped after the first, yielding a file that looked fine but was almost entirely encrypted.
Smooth Streaming manifests carry no range attributes, so every ISM video track was labelled SDR even when the stream is HDR10/HLG/DV, breaking range-based selection (-r HDR10 / -r DV) for ISM services.
- ism_init: walk the full HEVC SPS (incl. scaling-list and st_ref_pic_set skippers) to read the VUI colour triple (colour_primaries, transfer_characteristics, matrix_coeffs); expose parse_codec_private_data_colour() keyed by FourCC. No unshackle imports added.
- ism: new ISM.get_video_range() maps the CICP triple via Video.Range.from_cicp (PQ -> HDR10, HLG -> HLG, BT.709/absent -> SDR); DVHE/DVH1 FourCCs map straight to DV since DV bitstreams signal Unspecified (2,2,2) in the VUI. to_tracks() now sets range_ on every video track. Soft-fails to SDR on malformed data.
- ism: accept RnetSession in download_track() so TLS-impersonated sessions pass the type check.
- tests: real PQ/HLG/BT.709 (x265-minted) and Dolby Vision (live-manifest, DoViProfile=stn, out-of-order SPS,PPS,VPS NALs) CodecPrivateData samples; byte-level VUI assertions in test_ism_init and manifest->Range characterization in new test_ism_range.
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.
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