[FFmpeg-devel] hundred bucks to fix FLV cutting (STILL OPEN)

Cyrus A lists
Wed Jul 18 16:57:09 CEST 2007

Reimar D?ffinger wrote:
> Hello,
> On Mon, Jul 16, 2007 at 03:22:08PM -0400, Cyrus A wrote:
> [...]
>> I'm trying to cut a small portion out of a larger FLV file. I have an 
>> FLV file that is 156 seconds long. The command...
>> ffmpeg -ss 6 -t 100 -y -vcodec copy -acodec copy -i 
>> /home/cyrus/Desktop/test.flv /home/cyrus/Desktop/cut.flv
>> ...should create a file that is 94 seconds long (seeking 6 seconds, 
>> duration for 100 seconds). Instead, it creates a file 150 seconds long. 
>> That is, it seems to be seeking for 6 seconds, then giving me the rest 
>> of the clip. Any ideas why that's happening?
> Well, to ffmpeg it looks like everything is working right, the problem
> is:
>> Output #0, flv, to '/home/cyrus/Desktop/cut.flv':
>>   Stream #0.0: Video: flv, yuv420p, 480x384, q=2-31, 1000.00 fps(c)
> I think this will also create an output file with A-V sync that is
> extremely of, but in your case with a real framerate of 15, it takes
> 1000 seconds of video before ffmpeg things 15 have actually passed.
> I guess the frame rate is not actually know at the point where ffmpeg
> sets it for the output file. I don't know why specifying -r 15
> explicitly does not help.
Sorry, the patch doesn't do any seeking. Still starts from the beginning 
of the original file. It does cut the file (with -t) and Mplayer does 
say the file is 100 seconds long, which is an improvement.

Don't give up! Keep trying guys. I know somebody can get this ironed 
out. I wish I had a few weeks to immerse myself in ffmpeg and fix it 
myself, but for now, I'm relying on the brainiacs on this list.


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