While they shouldn't be present, they are harmless if they are.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: James Almer <jamrial@gmail.com>
The av_log() is done outside the lock, but this way the accesses to the
field (reads and writes) are always protected by a mutex. The av_log()
is not run inside the lock context because it may involve user callbacks
and doing that in performance-sensitive code is probably not a good idea.
This should fix occasional tsan warnings when running fate-h264, like:
WARNING: ThreadSanitizer: data race (pid=10916)
Write of size 4 at 0x7d64000174fc by main thread (mutexes: write M2313):
#0 update_context_from_user src/libavcodec/pthread_frame.c:335 (ffmpeg+0x000000df7b06)
[..]
Previous read of size 4 at 0x7d64000174fc by thread T1 (mutexes: write M2311):
#0 ff_thread_await_progress src/libavcodec/pthread_frame.c:592 (ffmpeg+0x000000df8b3e)
I'm hoping that this will address the remaining tsan fate-h264 issues:
WARNING: ThreadSanitizer: data race (pid=24478)
Read of size 8 at 0x7dbc0001c828 by main thread (mutexes: write M3243):
#0 ff_h264_ref_picture src/libavcodec/h264_picture.c:107 (ffmpeg+0x0000013b78d8)
[..]
Previous write of size 1 at 0x7dbc0001c82e by thread T2 (mutexes: write M3245):
#0 ff_h264_direct_ref_list_init src/libavcodec/h264_direct.c:137 (ffmpeg+0x000001382c93)
But I'm not sure because I haven't been able to reproduce locally.
Consider the following sequence of events:
- open a codec without AV_CODEC_CAP_DELAY
- decode call fails with an error
- ff_thread_flush() is called
- drain packet is sent
Then the last step would make ff_thread_decode_frame() return an error,
because p->result can still be set to an error value. This is because
submit_packet returns immediately if AV_CODEC_CAP_DELAY is not set, and
no worker thread gets the chance to reset p->result, yet its value is
trusted by ff_thread_decode_frame().
Fix this by clearing the error fields on flush.
Fixes tsan warnings like this in fate-vp8-test-vector-007:
WARNING: ThreadSanitizer: data race (pid=65909)
Write of size 4 at 0x7d8c0000e088 by thread T1:
#0 vp8_decode_mb_row_sliced vp8.c:2519 (ffmpeg:x86_64+0x100995ede)
[..]
Previous write of size 4 at 0x7d8c0000e088 by thread T2:
#0 vp8_decode_mb_row_sliced vp8.c:2519 (ffmpeg:x86_64+0x100995ede)
Fixes tsan warnings like this in fate-vp8-test-vector-007:
WARNING: ThreadSanitizer: data race (pid=3590)
Write of size 4 at 0x7d8c0000e07c by thread T2:
#0 decode_mb_row_no_filter src/libavcodec/vp8.c:2330 (ffmpeg+0x000000ffb59e)
[..]
Previous write of size 4 at 0x7d8c0000e07c by thread T1:
#0 decode_mb_row_no_filter src/libavcodec/vp8.c:2330 (ffmpeg+0x000000ffb59e)
This removes the last use of the ff_put/add_pixels_clamped global
function pointers, and as such they are removed.
This patch has a negative effect on performance on MIPS, since there's
a SIMD-optimized put/add_pixels_clamped, but no xvid or jrev. From a
code maintenance point of view, that is probably acceptable.
Because the global function pointers are removed, this fixes the following
tsan warnings when running e.g. fate-dnxhr-parse:
WARNING: ThreadSanitizer: data race (pid=29917)
Write of size 8 at 0x0000025b12d8 by thread T2 (mutexes: write M1543):
#0 ff_idctdsp_init src/libavcodec/idctdsp.c:313 (ffmpeg+0x00000044b68e)
[..]
Previous write of size 8 at 0x0000025b12d8 by thread T1 (mutexes: write M1541):
#0 ff_idctdsp_init src/libavcodec/idctdsp.c:313 (ffmpeg+0x00000044b68e)
These use the mmx IDCT, but sse2 put/add_pixels_clamped implementations.
This way we don't need to use the ff_put/add_pixels_clamped function
pointers.
Instead, hardcode the use of the _arm implementation of add_pixels,
and use the C version for put_pixels (as no arm-optimized version
exists). Since there's separate implementations of idct{,_put,_add}
for neon, this has no practical impact on performance.
This tries to handle cases where separate invocations of decode_frame()
(each running in separate threads) write to respective fields in the
same AVFrame->data[]. Having per-field owners makes interaction between
readers (the referencing thread) and writers (the decoding thread)
slightly more optimal if both accesses are field-based, since they will
use the respective producer's thread objects (mutex/cond) instead of
sharing the thread objects of the first field's producer.
In practice, this fixes the following tsan-warning in fate-h264:
WARNING: ThreadSanitizer: data race (pid=21615)
Read of size 4 at 0x7d640000d9fc by thread T2 (mutexes: write M1006):
#0 ff_thread_report_progress pthread_frame.c:569 (ffmpeg:x86_64+0x100f7cf54)
[..]
Previous write of size 4 at 0x7d640000d9fc by main thread (mutexes: write M1004):
#0 update_context_from_user pthread_frame.c:335 (ffmpeg:x86_64+0x100f81abb)
Fixes the following tsan warning when running fate-vsynth_lena-ffvhuff:
WARNING: ThreadSanitizer: data race (pid=6484)
Write of size 8 at 0x7d64000154b8 by main thread (mutexes: write M1331):
#0 update_context_from_user src/libavcodec/pthread_frame.c:331 (ffmpeg+0x000000dca887)
[..]
Previous read of size 8 at 0x7d64000154b8 by thread T2 (mutexes: write M1334):
#0 draw_slice src/libavcodec/huffyuvdec.c:857 (ffmpeg+0x000000bcc86f)
Add a codec capable of decoding some formats of the RFC4175. For now
it's only capable of handling YCbCr-4:2:2 with 8-bit or 10-bit depth.
For 8-bit it's a simple pass-through, for 10-bit it depacks the stream
in the AV_PIX_FMT_YUV422P10 pixel format.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Rostislav Pehlivanov <atomnuker@gmail.com>
Fixes tsan warnings in fate-apng:
WARNING: ThreadSanitizer: data race (pid=51230)
Read of size 4 at 0x7d50000042fc by main thread (mutexes: write M1000):
#0 frame_copy_props frame.c:302 (ffmpeg:x86_64+0x1019a35d6)
[..]
Previous write of size 4 at 0x7d50000042fc by thread T1 (mutexes: write M997):
#0 decode_idat_chunk pngdec.c:708 (ffmpeg:x86_64+0x100f5562a)
