avfilter: take_samples: do not directly return frame when samples are skipped

Multimedia / FFmpeg - Muhammad Faiz [gmail.com] - 20 May 2017 12:19 EDT

Modifying data pointer when skipping samples may make it unaligned. Workaround for Ticket6349.

This should fix the crash of ticket's testcase and a crash/regression with avxsynth (reported by Michael Niedermayer).

Also change frame->nb_samples < max to frame->nb_samples <= max. This improves performance. Benchmark: ./ffmpeg -filter_complex "aevalsrc=0:n=1166,firequalizer=fixed=on" -f null null old: 25767 decicycles in take_samples, 1023 runs, 1 skips 25422 decicycles in take_samples, 2047 runs, 1 skips 25181 decicycles in take_samples, 4095 runs, 1 skips 24904 decicycles in take_samples, 8191 runs, 1 skips

new: 550 decicycles in take_samples, 1024 runs, 0 skips 548 decicycles in take_samples, 2048 runs, 0 skips 545 decicycles in take_samples, 4096 runs, 0 skips 544 decicycles in take_samples, 8192 runs, 0 skips

fc3a03f avfilter: take_samples: do not directly return frame when samples are skipped
libavfilter/avfilter.c | 8 +++++++-
libavfilter/framequeue.c | 2 ++
libavfilter/framequeue.h | 5 +++++
3 files changed, 14 insertions(+), 1 deletion(-)

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