[Libav-user] Problems/confusion with videotoolbox encoding and frame rate

[Steve Green]

It seems like videotoolbox encoding (h264 in my case) is stuck at 25 fps.  I’ve modified one of the ffmpeg examples (encode_video) to encode at 60 fps, and at a resolution that videotoolbox likes.  640x480 in this case.  With x264, ffprobe will show 60 fps but with videotoolbox, it’s always 25.

Below is what Im doing and what ffprobe is showing:

$ ./encode_video /tmp/enc.flv h264_videotoolbox
[ output removed for brevity ]

$ ffprobe /tmp/enc.flv
[ some output removed for brevity ]
Stream #0:0: Video: h264 (High), yuv420p(progressive), 640x480 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 1200k tbn, 50 tbc

$ ./encode_video /tmp/enc.flv libx264
[ output removed for brevity ]

$ ffprobe /tmp/enc.flv
[ some output removed for brevity ]
Stream #0:0: Video: h264 (High), yuv420p(progressive), 640x480, 60 fps, 60 tbr, 1200k tbn, 120 tbc