On Thu, Apr 27, 2017 at 5:30 AM, Marton Balint <c...@passwd.hu> wrote: > > > On Wed, 26 Apr 2017, Ronald S. Bultje wrote: > >> Hi, >> >> On Wed, Apr 26, 2017 at 2:20 PM, Muhammad Faiz <mfc...@gmail.com> wrote: >> >>> On Wed, Apr 26, 2017 at 10:34 PM, Ronald S. Bultje <rsbul...@gmail.com> >>> wrote: >>> > Hi, >>> > >>> > On Wed, Apr 26, 2017 at 1:21 AM, Muhammad Faiz <mfc...@gmail.com> >>> > wrote: >>> > >>> >> On Wed, Apr 26, 2017 at 4:09 AM, wm4 <nfx...@googlemail.com> wrote: >>> >> > On Tue, 25 Apr 2017 23:52:04 +0700 >>> >> > Muhammad Faiz <mfc...@gmail.com> wrote: >>> >> > >>> >> >> when frame is received, not from other threads. >>> >> >> >>> >> >> Should fix fate failure with THREADS>=4: >>> >> >> make fate-h264-attachment-631 THREADS=4 >>> >> >> >>> >> >> Signed-off-by: Muhammad Faiz <mfc...@gmail.com> >>> >> >> --- >>> >> >> libavcodec/pthread_frame.c | 4 ++++ >>> >> >> 1 file changed, 4 insertions(+) >>> >> >> >>> >> >> diff --git a/libavcodec/pthread_frame.c >>> >> >> b/libavcodec/pthread_frame.c >>> >> >> index 13d6828..c452ed7 100644 >>> >> >> --- a/libavcodec/pthread_frame.c >>> >> >> +++ b/libavcodec/pthread_frame.c >>> >> >> @@ -547,6 +547,10 @@ int ff_thread_decode_frame(AVCodecContext >>> *avctx, >>> >> >> >>> >> >> fctx->next_finished = finished; >>> >> >> >>> >> >> + /* if frame is returned, properly set err from the thread that >>> >> return frame */ >>> >> >> + if (*got_picture_ptr) >>> >> >> + err = p->result; >>> >> >> + >>> >> >> /* return the size of the consumed packet if no error occurred >>> */ >>> >> >> if (err >= 0) >>> >> >> err = avpkt->size; >>> >> > >>> >> > Well, the logic confuses me. Does this override an earlier set err >>> >> > value? >>> >> >>> >> Yes, because an earlier set err value may be from a different thread. >>> >> >>> >> >Could err be set to the correct value in the first place (inside >>> >> > of the loop)? >>> >> >>> >> No, it was intended on 32a5b631267 >>> > >>> > >>> > Thanks for working on this. It's good to get more people familiar with >>> this >>> > code. >>> > >>> > So, I'm looking at understanding this, you're trying to fix the case >>> where >>> > during draining, we may iterate over >1 worker thread cases where the >>> first >>> > returned an error code without having decoded a frame, and the second >>> > decoded a frame without returning an error code, right? The current >>> > code >>> > would return a frame with an error return code, which I believe is then >>> > ignored by the user thread. >>> > >>> > So, you're basically trying to say that instead, we should ignore the >>> > error. I agree that fixes the issue of md5 mismatch w/ vs. w/o threads, >>> but >>> > I doubt that it's fundamentally more correct, because the user thread >>> still >>> > misses out on error codes from the worker threads. Wouldn't you agree >>> that >>> > we should - even during draining - not iterate over N threads, but just >>> the >>> > next thread, and return either an error or a decoded frame, and keep >>> doing >>> > that until all worker threads are flushed, which we can then signal >>> > e.g. >>> by >>> > return=0 and *got_picture_ptr=0? >>> >>> The problem is that return<0 and *got_picture_ptr==0 is also >>> considered as eof when avpkt->size==0. >> >> >> >> This will probably count as an API change then, but my thinking is that we >> should add a new API that "fixes" the above. The old API can then skip >> error-packets-on-flush (similar to how your patch does it). >> >> Or do people dislike this? > > > I propose the following: > > Using the old (and deprecated) public API you should simply get an error. > Losing more frames in the end if threading is invovled is acceptable IMHO. > Sliently ignoring an error is not.
Error is not silently ignored. Only reordered, and returned after all frames are flushed > > Using the new public API you should get the error code, then the proper > frame on the next call. In the new public API only AVERROR_EOF signals EOF, > so this seems doable. Sound good. Are all decoders ready for this? I mean, a guarantee that they don't return error infinitely on eof? > > Or do I miss something? Or I just stated the obvious? :) _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
