Hi Ronald, actually the problem was occurring transcoding quicktime files with ProRes settings and not with h264. Changing the number of threads would not solve the problem. I noticed that memory usage would keep growing as long i reached a certain point at which i would get a message like "Delay between the first packet and last packet in the muxing queue is 10004900 > 10000000: forcing output". When transcoding 8k files i would not get to this point as at 4GB the app would crash. The solution at the moment is to set the output format context's "max_interleave_delta" at a value lower than 10000000 after the output context is allocated and before avformat_write_header(). Doing this i am forcing the encoder to output frames, memory usage is kept steady, and i managed to transcode 8k files with no errors. But is this a correct workaround? Or should i set some flag too? I tried also to set the output context flag to AVFMT_FLAG_SHORTEST but i am not getting the same result.
Thank you, bye, Simone. ________________________________________ From: Simone Donadini Sent: Friday, March 15, 2019 11:42 AM To: FFmpeg development discussions and patches Subject: RE: [FFmpeg-devel] 32bit transcoding app running out of memory Hi Ronald, yes, we are using our own codec wrapped inside FFmpeg. Thank you for your suggestion, i will try with limiting the number of threads launched by FFmpeg. Simone. ________________________________________ From: ffmpeg-devel [ffmpeg-devel-boun...@ffmpeg.org] on behalf of Ronald S. Bultje [rsbul...@gmail.com] Sent: Friday, March 15, 2019 11:24 AM To: FFmpeg development discussions and patches Subject: Re: [FFmpeg-devel] 32bit transcoding app running out of memory Hi, On Thu, Mar 14, 2019 at 7:52 AM Simone Donadini < simone.donad...@avolites.com> wrote: > > 2019-03-14 11:28 GMT+01:00, Simone Donadini < > simone.donad...@avolites.com>: > > > While transcoding video files with larger resolution (8K) the app, > > > which is 32bit, will run out of memory (>4GB). > > > It does not look like a memory leak, as memory usage will grow as long > as > > > transcoding a certain amount of frames and then it will stay steady. It > > > looks like the amount of memory usage depends on the resolution of the > > > > > frame, but even with a 8K frame using >4GB is not expected. > > > > Why do you think so? > > With our codec one encoded frame 7680x4320 should be ~100MB. > Am I right in interpreting this as that you're not actually using an existing FFMpeg encoder, but rather your own codec's encoder wrapped into FFmpeg by yourself? > h264 8K @60fps I think several dozen frame allocations in the decoder (b/c of frame threading) can happen, depending on the machine. 8*4*1.5*2=96MB/frame (assuming 10bits 8K, you didn't mention), so for 3 dozen (assuming n_threads=20-30), we're talking 3.6GB. To limit, use ffmpeg -thread_type none -i .. or ffmpeg -threads $n -i .. where $n is a smaller number (e.g. 2 or 4) than the default (which is system-dependent). Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
