[NicolasHug]

This is part of a stack that adds demuxer-free decoding to the low-level APIs: decoding packets that don't come from a Demuxer (#1585), demuxing and decoding in different processes, and raw H.264 / HEVC streams (#1771).

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Raw H.264 / HEVC elementary streams have no timestamps, so FFmpeg can't seek them to a timestamp. That made VideoStream.scan() fail, because it rewinds the demuxer before and after reading the stream, and made Demuxer.seek() fail entirely (#1771).

• Rewinding: seek(0) now rewinds such streams by byte offset, so scan() works too.
• Other seeks: seeking anywhere else still raises, with an explanation. Seeking raw streams to keyframes could be a follow-up.
• FrameIndex:
  • pts_seconds is NaN for frames without a pts.
  • index_at() and key_frame_seconds_for() raise on a stream with no timestamps at all.
  • The frame count, durations and keyframe positions are available. Without timestamps, those are in decoding order, which for open GOPs isn't where keyframes are displayed. The docs say so, and a test uses an open-GOP HEVC stream.

VideoDecoder still doesn't support raw streams: the low-level APIs are where they're handled.

Part of #1771.

Tests

• scan() on raw H.264 and HEVC streams.
• Rewinding mid-stream gives the same packets.
• Seeking elsewhere raises.

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[pytorch-bot]

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❌ 19 New Failures, 10 Unrelated Failures

As of commit ba2c9c4 with merge base ffb098a ():

NEW FAILURES - The following jobs have failed:

• Lint / pre-commit-checks (3.12) (gh)
• Linux CPU x86 / install-and-test (3.11, 4) (gh)
  test/test_decoders.py::TestLowLevel::test_audio_decoder_parameters_round_trip_through_their_fields[asset3]
• Linux CPU x86 / install-and-test (3.11, 5) (gh)
  test/test_decoders.py::TestLowLevel::test_rewind_stream_without_timestamps
• Linux CPU x86 / install-and-test (3.11, 6) (gh)
  test/test_decoders.py::TestLowLevel::test_coded_side_data_requires_ffmpeg_6_1
• Linux CPU x86 / install-and-test (3.11, 9) (gh)
  An unexpected error has occurred. Conda has prepared the above report.
• Linux CUDA aarch64 / install-and-test (3.11, 13.0, 9) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.0, 6) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.0, 7) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.0, 8) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.0, 9) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.2, 4) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.2, 6) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.2, 7) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.2, 8) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• Linux CUDA x86 / install-and-test (3.11, 13.2, 9) (gh)
  test/test_decoders.py::TestLowLevel::test_decode_in_another_process
• MacOS / install-and-test (3.11, 4) (gh)
  test/smoke_test.py::TestLowLevelAPIs::test_audio_pipeline
• Windows CPU / Build and Upload wheel / build-wheel-py3_11-cpu (gh)
• Windows CPU / Build and Upload wheel / upload / upload-wheel-py3_11-cpu (gh)
• Windows CUDA / install-and-test (3.11, 13.2, 4) (gh)
  test/smoke_test.py::TestLowLevelAPIs::test_audio_pipeline

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• Linux CPU x86 / install-and-test-no-ffmpeg (3.11) (gh) (detected as infra flaky with no log or failing log classifier)
• Linux CUDA aarch64 / install-and-test (3.11, 13.0, 4) (gh) (detected as infra flaky with no log or failing log classifier)
• Linux CUDA x86 / install-and-test (3.11, 13.0, 4) (gh) (detected as infra flaky with no log or failing log classifier)
• Linux CUDA x86 / install-and-test-no-ffmpeg (gh) (detected as infra flaky with no log or failing log classifier)
• Windows CUDA / install-and-test (3.11, 13.0, 4) (gh) (similar failure)
  Unable to download artifact(s): Artifact not found
• Windows CUDA / install-and-test (3.11, 13.0, 7) (gh) (detected as infra flaky with no log or failing log classifier)
• Windows CUDA / install-and-test (3.11, 13.0, 9) (gh) (similar failure)
  Unable to download artifact(s): Artifact not found

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• Windows CUDA / install-and-test (3.11, 13.0, 6) (gh) (trunk failure)
  Unable to download artifact(s): Artifact not found
• Windows CUDA / install-and-test (3.11, 13.0, 8) (gh) (trunk failure)
• Windows CUDA / install-and-test-on-cpu-only-machine (gh) (trunk failure)
  Unable to download artifact(s): Artifact not found

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