[FFmpeg-devel] FPS detection when h264 file is decoded

[Tomas Härdin]

On Thu, 2010-12-02 at 10:22 +0900, William K. Kang wrote:
> Hi,
> 
> When ffmpeg decodes h264 file, there is a symptom that ffmpeg?s fps is half
> of the original frame rate.
> [kwkang at aLinux ffmpeg-0.6.1]$ ./ffmpeg -i /pub/kwkang/h264/test_60.h264
> FFmpeg version 0.6.1, Copyright (c) 2000-2010 the FFmpeg developers
>   built on Nov 29 2010 14:14:35 with gcc 4.3.2 20081105 (Red Hat 4.3.2-7)
>   configuration:
>   libavutil     50.15. 1 / 50.15. 1
>   libavcodec    52.72. 2 / 52.72. 2
>   libavformat   52.64. 2 / 52.64. 2
>   libavdevice   52. 2. 0 / 52. 2. 0
>   libswscale     0.11. 0 /  0.11. 0
> [h264 @ 0x2b8d420]max_analyze_duration reached
> [h264 @ 0x2b8d420]Estimating duration from bitrate, this may be inaccurate
> 
> Seems stream 0 codec frame rate differs from container frame rate: 60.00
> (60/1) -> 30.00 (60/2)
> Input #0, h264, from '/pub/kwkang/h264/test_60.h264':
>   Duration: N/A, bitrate: N/A
>     Stream #0.0: Video: h264, yuv420p, 1920x1088 [PAR 1:1 DAR 30:17], 30
> fps, 30 tbr, 1200k tbn, 60 tbc
> At least one output file must be specified
> 
> Frame rate of test_60.h264 is 60 but ffmpeg is telling it is 30 fps.
> Could you know why?
> 
> Thanks

60 Hz is probably the field rate rather than the frame rate, assuming
the video is interlaced. Also, questions like these belong in
ffmpeg-user.

/Tomas
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20101202/a7145230/attachment.pgp>