[FFmpeg-user] Save webcam stream in mpg, not avi format

[Felix Baier]

Hi Eugen —

I have done some more testing of the code and run the camera for a night. I should get 8-9 videos of each one hour length per night. However, I get 4 videos of one hour length, but at twice the speed. The frame rate apparently is unaffected by this (still 25fps), at least as far as it is displayed in the properties of the videos.

I changed “-vcodec mpeg4 -qscale 2” to “-vcodec mpeg4 -q:v 2” after I got a notification that the first version was ambiguous. The complete code I used:

ffmpeg -r 25 -f dshow -s 640x480 -i video="Microsoft LifeCam HD-5000” -vcodec mpeg4 -q:v 2 -f segment -segment_time 3600 -reset_timestamps 1 -segment_start_number 1 -segment_format avi -r 25 c:\Users\Desktop\out%%03d.avi

Any idea what might be going on?

Leo

> On Aug 5, 2015, at 11:24 AM, Felix Baier <felixbaier at yahoo.de> wrote:
> 
> 
>> 
>>> Thus, is it possible to save in avi format, but use 
>>> a different codec that will generate smaller files?
>> 
>> Yes, try "-vcodec mpeg4 -qscale 2" or 
>> "-vcodec mpeg1video -mbd 2 -qscale 2" or use h264.
>> 
>> Carl Eugen
> 
> “-vcodec mpeg4 -qscale 2” reduces the file size by a factor of 50 and can be opened in my downstream analysis Ethovision. It will take a week or so to run some real experiments and see if the video quality is good enough, but it looks great and I’m optimistic that this solved the problem. Thanks for your suggestions! They really made a difference.
> 
> Leo
>