topic Audio timing problems with the UMC library in Intel® Integrated Performance Primitives https://community.intel.com/t5/Intel-Integrated-Performance/Audio-timing-problems-with-the-UMC-library/m-p/857292#M7345 <P>Hello "jgaa":</P> <P>Sorry for such a long delay in responding to your question. Is this still an outstanding issue for you? Checking for the file link you cite in your post I find no file.</P> <P>Please let us know if this issue is still outstanding for you so we can provide help.</P> <P>Regards,</P> <P>Paul</P> Tue, 26 Jan 2010 07:20:12 GMT PaulF_IntelCorp 2010-01-26T07:20:12Z Audio timing problems with the UMC library https://community.intel.com/t5/Intel-Integrated-Performance/Audio-timing-problems-with-the-UMC-library/m-p/857291#M7344 Hi,<BR /><BR />I'm playing a bit with the UMC library. I've written a very simple screen-recorder (under Windows) that also captures the microphone. Since I'm actually creating the video, I cannot depend on some fixed fps to set the time-stamps, so internally, I use a timer with 1 ms (theoretical) resolution (from Windows SDK timeGetTime()). <BR /><BR />I use the H264 video-codec and AAC audio-codec with the MP4 muxer. Initially I had some problems with the time-stamps for the video-frames as well, but when I convert my internal milliseconds with timestamp = (ms / 1000.0), the video plays back in (visually) correct speed. The audio is an entirely different story. Using the same conversion, I get audio in high speed, aligned to the first 50% of the video. That is, if I feed PCM-buffers to the audio-codec in the size requested by the codec (audio_params_.m_SuggestedInputSize). If I feed the larger buffers that I request from Windows, it seems like the encoder or muxer splits the buffer into smaller frames, and then mess up the timestamps of the individual frames - this is at least what the VLC player indicates ("timing screwed, stopping resampling")).<BR /><BR />So my question is - what is the actual timestamps expected by the AAC audio-codec and the MP4 muxer? And, are they relative to the start of the movie, or to the previous audio-segment?<BR /><BR />The complete source-code for my test-project can be found here: <A href="http://war.jgaa.com/files/IPP-test.7z" target="_blank">http://war.jgaa.com/files/IPP-test.7z</A><BR /> Fri, 18 Dec 2009 15:10:20 GMT https://community.intel.com/t5/Intel-Integrated-Performance/Audio-timing-problems-with-the-UMC-library/m-p/857291#M7344 jgaa 2009-12-18T15:10:20Z Audio timing problems with the UMC library https://community.intel.com/t5/Intel-Integrated-Performance/Audio-timing-problems-with-the-UMC-library/m-p/857292#M7345 <P>Hello "jgaa":</P> <P>Sorry for such a long delay in responding to your question. Is this still an outstanding issue for you? Checking for the file link you cite in your post I find no file.</P> <P>Please let us know if this issue is still outstanding for you so we can provide help.</P> <P>Regards,</P> <P>Paul</P> Tue, 26 Jan 2010 07:20:12 GMT https://community.intel.com/t5/Intel-Integrated-Performance/Audio-timing-problems-with-the-UMC-library/m-p/857292#M7345 PaulF_IntelCorp 2010-01-26T07:20:12Z