[Ffmpeg-devel] Wrong duration in a nut container

Rich Felker dalias
Fri Aug 12 04:05:58 CEST 2005

On Fri, Aug 12, 2005 at 01:14:35AM +0200, Michael Niedermayer wrote:
> Hi
> On Thu, Aug 11, 2005 at 02:47:03PM +0200, Hendrik Schmal wrote:
> > Hello,
> > 
> > I want to grab a video from tape (via framegrabber (bt8x8), no audio, SuSE 
> > Linux 8.2). I use the FFMpeg-20050806.tar.bz2 package.
> > 
> > The following commandline (see below) should give me a video containing 250 
> > frames (that means 5secs on 50fps).
> > 
> > With the avi format I get a duration of 5 secs. The nut format shows me a 
> > wrong duration, but it also contains 250 frames. 
> > This happens when for example the tape partially contains no data.
> > 
> > The same behaviour I have using the FFmpeg API (libavformat/libavcodec).
> > 
> > I can't use avi, because of my videos are larger than 1GB.
> > 
> > Is this a bug or did I something wrong ?
> nuts duration field is in a info packet and thats neither stored nor read
> currently, patch welcome

IMO using the info field is a very bad idea. For instance people might
framecopy a nut file to make a small excerpt, and keep all the info
headers. Then the total length will be wrong. Instead the demuxer
should seek to the end and read the last timestamps to find total
length.. It will already be seeking to end to read index anyway, and
if there's an index it can just get total length from the index.


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