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POFiles created with a direct stream copy using FFmpeg's libavformat API play back too fast at 3600 fps
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  1. POFiles created with a direct stream copy using FFmpeg's libavformat API play back too fast at 3600 fps
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    copied!<p>I am working on a libavformat API wrapper that converts MP4 files with H.264 and AAC to MPEG-TS segments suitable for streaming. I am just doing a simple stream copy without re-encoding, but the files I produce play the video back at <strong>3600 fps</strong> instead of 24 fps.</p> <p>Here are some outputs from ffprobe <a href="https://gist.github.com/chrisballinger/6733678" rel="nofollow noreferrer">https://gist.github.com/chrisballinger/6733678</a>, the broken file is below:</p> <pre><code>r_frame_rate=1/1 avg_frame_rate=0/0 time_base=1/90000 start_pts=0 start_time=0.000000 duration_ts=2999 duration=0.033322 </code></pre> <p>The same input file manually sent through ffmpeg has proper timestamp information:</p> <pre><code>r_frame_rate=24/1 avg_frame_rate=0/0 time_base=1/90000 start_pts=126000 start_time=1.400000 duration_ts=449850 duration=4.998333 </code></pre> <p>I believe the problem lies somewhere in my setup of libavformat here: <a href="https://github.com/OpenWatch/FFmpegWrapper/blob/master/FFmpegWrapper/FFmpegWrapper.m#L349" rel="nofollow noreferrer">https://github.com/OpenWatch/FFmpegWrapper/blob/master/FFmpegWrapper/FFmpegWrapper.m#L349</a> where I repurposed a bunch of code from ffmpeg.c that was required for the direct stream copy.</p> <p>Since 3600 seems like a "magic number" (60*60), it could be as simple as me not setting the time scale properly, but I can't figure out where my code diverges from ffmpeg/avconv itself.</p> <p>Similar question here, but I don't think they got as far as I did: <a href="https://stackoverflow.com/questions/15239124/muxing-a-h-264-annex-b-aac-stream-using-libavformat-with-vcopy-acopy">Muxing a H.264 Annex B &amp; AAC stream using libavformat with vcopy/acopy</a></p>
 

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