ffmpeg question

[Joe Auty]

Got it!

This bug is fixed in ffmpeg-devel...

I think I'm good now.


I hope my thinking through this problem outloud on the list will be  
of some use to some, and not simply spam. I'll try to be quiet now =)

On Apr 15, 2006, at 1:53 AM, Joe Auty wrote:

> Okay, I think I figured this out.... almost:
>
> ffmpeg -i /dev/cxm0 -vcodec copy -acodec copy -t 20 test_ffmpeg.mpg
>
>
> Except doing this completely ignores my -t 20 and keeps on  
> recording after 20 seconds... why is that?
>
>
> On Apr 15, 2006, at 1:14 AM, Joe Auty wrote:
>
>>
>> On Apr 15, 2006, at 1:10 AM, Jacob Meuser wrote:
>>
>>> On Fri, Apr 14, 2006 at 11:54:18PM -0400, Joe Auty wrote:
>>>> Hello,
>>>>
>>>> Doing a:
>>>>
>>>> cat /dev/cxm0 > myvideo.mpg
>>>>
>>>> produces great mpeg2 video... However:
>>>>
>>>> ffmpeg -i /dev/cxm0 -t 10 test_ffmpeg.mpg
>>>>
>>>> produces 10 seconds of mpeg1 video that doesn't look as good.
>>>>
>>>>
>>>> I've tried adding -f <format> and -vcodec options with -s 640x480,
>>>> but I just can't seem to find something that will reproduce my raw
>>>> feed without errors, loss of picture, the size being off, or
>>>> reverting back to mpeg1.
>>>>
>>>> To save me a little further time in just random trial and error,  
>>>> can
>>>> anybody hook me up with the combination I need?
>>>
>>> sorry, but what exactly are you trying to do?  what is lacking with
>>> the cat command?
>>>
>>> most likely, if you are running a transcoder (like ffmpeg, mencoder
>>> or transcode), it is decoding the input into raw YUV or RGB and then
>>> back to MPEG.  this is a lossy and time/cpu consuming process.
>>>
>>
>> The cat command works perfectly, but I'm trying to script it, and  
>> since you can use ffmpeg to specify how many seconds of footage to  
>> capture I'm trying to make this work.
>>
>> According to Quicktime's Get Info, the cat files are mpeg2... I'd  
>> like to know the best way to preserve the same quality from the  
>> cat command using ffmpeg.
>>
>> Am I starting to make sense now?
>>
>>
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>