[FFmpeg-user] fps in March 13 git: -r 29.97 = 2997 tbn ???

[Leo Izen]

On Sat, Apr 2, 2011 at 3:28 PM, sean darcy <seandarcy2 at gmail.com> wrote:

> On 04/02/2011 07:50 AM, Mike Scheutzow wrote:
>
>> sean darcy wrote:
>>
>>> Converting to an android playable file, I can't seem to set the fps.
>>> The input is 29.97. I tried setting -r to 29.97:
>>>
>>> ...
>>>
>>> Output #0, ipod, to 'OUTPUT1.m4v':
>>> Metadata:
>>> encoder : Lavf52.102.0
>>> Stream #0.0: Video: libx264, yuv420p, 720x480 [PAR 8:9 DAR 4:3],
>>> q=0-69, pass 1, 10000 kb/s, 30k tbn, 29.97 tbc
>>>
>>> tbn is the framerate for the AVStream of the container, as I gather
>>> from google. It seems that -r affects tbn of the output. But really
>>> oddly.
>>>
>>> How do I set fps of the output?
>>>
>>>
>> You misunderstand the meaning of tbn. tbn is not the "framerate" of the
>> container, it is the timebase.
>>
>> A timebase is like a clock, and indicates ticks per second. Generally,
>> higher values are better.
>>
>> Both values of tbn you saw should work fine for your file. You got
>> different values because 29.97 is not *exactly* equal to 30000/1001.
>>
>> Also, be careful believing the tbn / tbc "Output #0" stats - they have
>> been broken for months. Use 'ffmpeg -i infile' to get accurate values.
>>
>> Mike Scheutzow
>>
>
> Maybe more accurate, but much more confusing:
>
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'OUTPUT1.m4v':
>  Metadata:
>    major_brand     : M4V
>    minor_version   : 512
>    compatible_brands: isomiso2avc1
>    creation_time   : 2011-04-02 03:00:26
>    encoder         : Lavf52.102.0
>  Duration: 00:05:44.34, start: 0.000000, bitrate: 9920 kb/s
>    Stream #0.0(und): Video: h264 (High), yuv420p, 720x480 [PAR 8:9 DAR
> 4:3], 9916 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
>
> This is not interlaced, why 59.94? And tbn, whatever it is, is 30,000???
>

Here's one where none of the numbers match:

Input #0, mpeg, from 'IndianaJones3.vob':
  Duration: 02:06:52.96, start: 1.000000, bitrate: 6245 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480 [PAR
32:27 DAR 16:9], 9800 kb/s, 23.98 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s


>
> sean
>
>
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