[FFmpeg-user] -t option is ignored

[Tim Nicholson]

On 27/04/12 02:12, Steve Cookson wrote:
>[...]
> 
> ffmpeg -ss 5 -t 20 -i /home/image/Documents/Endoscopia/media/v_157_55_0.avi
> -vcodec huffyuv -r 10 -sameq -an -y
> /home/image/Documents/Endoscopia/media/v_157_55_63.avi
> 

and if you move the -t to after the input file what happens?

> [..]
>   Duration: 00:01:01.72, start: 0.000000, bitrate: 3574 kb/s
>     Stream #0.0: Video: mpeg4, yuv420p, 720x480 [PAR 12:11 DAR 18:11], 29.97
> tbr, 29.97 tbn, 29.97 tbc
>     Stream #0.1: Audio: adpcm_ima_wav, 48000 Hz, 2 channels, s16, 384 kb/s
> Incompatible pixel format 'yuv420p' for codec 'huffyuv', auto-selecting
> format 'yuv422p'
> 

Hmm, so the source frame rate is 29.97, and you want the output
framerate to be 10fps, so at roughly 3:1 ratio 20 secs of source will
give 60 secs of final file which is about what you got.....


> [buffer @ 0x1af4080] w:720 h:480 pixfmt:yuv420p
> 
> [ffsink @ 0x1afb8c0] auto-inserting filter 'auto-inserted scaler 0' between
> the filter 'src' and the filter 'out'
> [scale @ 0x1aec320] w:720 h:480 fmt:yuv420p -> w:720 h:480 fmt:yuv422p
> flags:0x4
> [huffyuv @ 0x1af46e0] using huffyuv 2.2.0 or newer interlacing flag
> Output #0, avi, to '/home/image/Documents/Endoscopia/media/v_157_55_63.avi':
>   Metadata:
>     SGMA            : Created by Sigma Designs EM8560 PVR Platform.
>     ISFT            : Lavf53.3.0
>     Stream #0.0: Video: huffyuv, yuv422p, 720x480 [PAR 12:11 DAR 18:11],
> q=2-31, 200 kb/s, 10 tbn, 10 tbc
> Stream mapping:
>   Stream #0.0 -> #0.0
> Press ctrl-c to stop encoding
> frame=   72 fps=  0 q=0.0 size=   23336kB time=7.20 bitrate=26551.4kbits/s
> dup=0frame=  150 fps=149 q=0.0 size=   49227kB time=15.00
> bitrate=26884.3kbits/s dup=frame=  228 fps=151 q=0.0 size=   74467kB
> time=22.80 bitrate=26755.8kbits/s dup=frame=  305 fps=152 q=0.0 size=
> 99419kB time=30.50 bitrate=26703.0kbits/s dup=frame=  383 fps=153 q=0.0
> size=  124272kB time=38.30 bitrate=26580.7kbits/s dup=frame=  461 fps=153
> q=0.0 size=  149386kB time=46.10 bitrate=26546.0kbits/s dup=frame=  538
> fps=153 q=0.0 size=  174522kB time=53.80 bitrate=26574.1kbits/s dup=frame=
> 568 fps=153 q=0.0 Lsize=  184319kB time=56.80 bitrate=26583.5kbits/s dup=0
> drop=1161    
> video:184300kB audio:0kB global headers:0kB muxing overhead 0.010273%
> 
> 
> 
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-- 
Tim