[Ffmpeg-devel] Capturing every keyframe from a DVD

[Rich Felker]

On Mon, Jun 13, 2005 at 09:54:04PM +0200, Michael Niedermayer wrote:
> Hi
> 
> On Monday 13 June 2005 21:21, Rich Felker wrote:
> > On Mon, Jun 13, 2005 at 04:50:06PM +0200, M?ns Rullg?rd wrote:
> > > Clayton Brown <clayton.brown at digitalrum.com> writes:
> > > > Does anyone know how to save every keyframe from a DVD into a format
> > > > such as JPG/TIFF etc.
> > >
> > > Extract the video stream, and send it through an AVParser.  Discard
> > > any non-I frames, and decode the I frames using libavcodec as usual.
> > > Save the decoded frames to separate images using your favorite library
> > > for your format of choice (libavcodec/libavformat handles some of
> > > them).
> >
> > Actually there should be a way to convert mpeg1(/2/4?) keyframes into
> > jpeg files losslessly without decoding and reencoding, shouldn't
> > there? :)
> 
> no, not really, unless you use lossless jpeg or accept the differences from 
> different quantization & colorspace

i thought jpeg allowed custom quantization, which could be set up to
match mpeg.

rich