Stage 2 PR-A1b: tools/daedalus_decode_h264 — H.264 standalone test harness #13
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Reference: marfrit/daedalus-decoder#13
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Option A's standalone end-to-end gate against real H.264 streams. First iteration: identity-passthrough validation. daedalus-decoder produces output byte-exact to libavcodec's
AVFramewhen fed the reconstructed pixels aspredicted, zero coeffs, no deblock edges.Validates the daedalus-decoder data path (
append_mb+flush_frame+ NV12 output + coded-vs-display dim handling) at real-stream frame sizes (320×240 and 1920×1088) with real H.264-decoded predicted-sample distributions — not the synthetic random patterns existingtest_idct_bitexact+test_deblock_smokeuse.Identity-passthrough math
mb_input.predicted= AVFrame pixels at MB raster positionmb_input.coeffs= 384 int16's, all zeromb_input.edges= NULL,n_edges = 0flush_frame:scratch_y/_uvpre-fill frompredicted(= AVFrame pixels)Result MUST equal AVFrame pixels byte-for-byte.
Build
New cmake option
DAEDALUS_BUILD_TOOLS(default OFF). When enabled, pkg-checks libavcodec / libavformat / libavutil and buildsdaedalus_decode_h264against the system FFmpeg. Stock libavcodec is sufficient for THIS PR — identity passthrough reads fromAVFrameafteravcodec_receive_frame; no per-MB internal state extraction needed yet.Usage
Exit codes: 0 = byte-exact match, 1 = arg/setup error, 2 = decode error, 3 = daedalus-decoder error, 4 = bit-exact comparison failed.
Result on hertz (Pi 5 V3D 7.1)
I-only test clips via
ffmpeg testsrc2 + libx264 -bf 0 -g 1:Followups
sl->mb, predicted-before-residual from prediction kernels, bS/alpha/beta — flows intomb_inputinstead of zeros, and IDCT / deblock dispatches do real GPU work. That's when daedalus-decoder is decoding real H.264 streams for real.Option A's standalone end-to-end gate against real H.264 streams. First iteration: identity-passthrough validation — daedalus-decoder produces output byte-exact to libavcodec's AVFrame when fed the reconstructed pixels as `predicted`, zero coeffs, no deblock edges. Validates: daedalus-decoder data path (append_mb + flush_frame + NV12 output + coded-vs-display dim handling) at real-stream frame sizes (320x240 and 1920x1088) with real H.264-decoded predicted- sample distributions — not the random patterns the existing test_idct_bitexact + test_deblock_smoke synthesize. Identity-passthrough math: - mb_input.predicted = AVFrame pixels at MB raster position - mb_input.coeffs = 384 int16's, all zero - mb_input.edges = NULL, n_edges = 0 flush_frame: scratch_y/_uv pre-fill from predicted (= AVFrame pixels) IDCT dispatches with all-zero coeffs add 0 (no-op compute) No deblock dispatches (no edges) copy-out → caller's NV12 planes Result MUST equal AVFrame pixels byte-for-byte. Build ----- New cmake option DAEDALUS_BUILD_TOOLS (default OFF). When enabled, pkg-checks libavcodec / libavformat / libavutil and builds the daedalus_decode_h264 binary against the system FFmpeg. Stock libavcodec is sufficient for THIS PR (identity passthrough reads from AVFrame after avcodec_receive_frame; no per-MB internal state extraction needed). Follow-up PRs (A2+) will use the per-MB inspection callback added in marfrit-packages patch 0016 (PR #106) to feed REAL per-MB state (pre-residual predicted samples, residual coeffs, deblock edges) for actual non-trivial daedalus-decoder validation. Usage ----- daedalus_decode_h264 [--substrate cpu|qpu|auto] [--max-frames N] <input.h264> <output_dadec.yuv> <output_ref.yuv> Exit codes: 0 = byte-exact match across all frames 1 = argument / setup error 2 = decode error from libavcodec 3 = daedalus-decoder error (ctx, append, flush) 4 = bit-exact comparison failed Result on hertz (Pi 5 V3D 7.1) ------------------------------ I-only test clip via ffmpeg testsrc2 + libx264 -bf 0 -g 1: 320x240, 5 frames: substrate=auto: Y diff 0/76800 UV diff 0/38400 PASS substrate=cpu: Y diff 0/76800 UV diff 0/38400 PASS substrate=qpu: Y diff 0/76800 UV diff 0/38400 PASS 1920x1088 (coded; 1080 display), 3 frames: substrate=auto: Y diff 0/2088960 UV diff 0/1044480 PASS Followups --------- - PR-A2: wire the per-MB inspection callback (marfrit-packages 0016) so per-MB state — coeffs (sl->mb), predicted-before- residual (from prediction kernels), bS/alpha/beta — flows into mb_input instead of zeros, and IDCT / deblock dispatches do real GPU work. At that point we're decoding real H.264 streams through daedalus-decoder for real. - PR-A3: extend to P/B frames once MC dispatch lands.