[theora] More examples?

Manuel Dahmen manuel.dahmen at gmail.com
Mon Feb 25 06:23:28 PST 2008

On Mon, 25 Feb 2008 13:31:37 +0100
Manuel Dahmen <manuel.dahmen at gmail.com> wrote:

OK I think I ll use etheora which seems simpler to encode and decode
theora videos than libtheora

> Hello,
> I want to make a program to extract frame from a theora movie as
> images. I tried with the decoding example located at theora web site
> (dump_video.c. I use it to extract a frame as yuv image but when I try
> to convert it to ppm with yuvtoppm program i obtain a strange image
> ( see http://poux.be/tmp/file.ppm ). I think it's a problem with the
>  byte order for yuv, but don't I don't know anything about this
> format.
> I'd like to make a simple program to encode chosen frame into ppm.
> Perhaps it's just ordering properly the bytes issued from the
> write_video() function in the example and using yuvtoppm to make the
> conversion.
> What is the yuv format issued from dump_video.c (444, 422, 420 ?) and
> when can I find a not-too-hard-to-understand explanation of this
> format?
> Thanks in advance for your answers.

Manuel Dahmen

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