NVIDIA's decode support matrix: the compute GPUs A100 (GA100) and H100 (GH100) have no
AV1 NVDEC decoder; only Ada (L4/L40/RTX40) and some Ampere (A10/A40/A16) do. So on
A100/H100 nodes, AV1 datasets must be decoded on CPU or re-encoded to H.265/H.264 — no
torchcodec build enables cuda AV1 decode there. Also distinguish that error from
"Unsupported device: cuda (variant: ffmpeg)", which is a torchcodec-built-without-CUDA
issue. Update diagnose_decode.py message + benchmark README accordingly.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- benchmark: raise SystemExit if 0 frames were measured, so a run that produces no
batches (swallowed decode error, all batches dropped) fails loudly instead of being
reported green with NaN/zero numbers (the misleading "COMPLETED" CUDA jobs).
- add benchmarks/streaming/diagnose_decode.py: isolates the streaming decode path
(resolve path -> fsspec.open -> torchcodec VideoDecoder -> get one frame) and prints
package versions + the first bytes of the handle. Pinpoints decode failures: bad/
placeholder bytes vs ffmpeg/torchcodec build issue. RoboCasa videos are AV1; the
failure message calls out AV1 decoder + NVDEC-on-Ada requirements explicitly.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Pepijn