Hi,

er0ck schrieb:
> aha!   right you are!
> 
[...]
> so it's about 12 frames of jpegs  (one of the "jpeg" must have wrapped over)
> so maybe i don't need mjpeg tools?  i just need to split up the 
> individual jpegs.

Yes. It's one of those "multipart jpeg" files. It should be trivial to
extract the individual images. Just parse the "Content-length:" fields.

[...]
> i had tried putting the mjpeg from the camera into an avi container thusly:
> $>mencoder 20071203_205830.mjpeg -o 20071203_205830.avi -ovc copy -of avi
> ....
> Video stream: 51535.333 kbit/s  (6441916 B/s)  size: 3092120 bytes  
> 0.480 secs  12 frames
> 
> and that worked as far as mplayer was concerned (obviously)
> but what is strange is that file (or i guess the avi container) still 
> thinks  there is an mjpeg encoded file inside:
> $> file 20071203_205830.avi
> 20071203_205830.avi: RIFF (little-endian) data, AVI, 1280 x 1024, 25.00 
> fps, video: Motion JPEG

No, it's not strange it's exactly what it ought to be. Your mencoder command
just extracts the JPEGs and puts them into an AVI
container. The container is now AVI, but the video is still (M)JPEG.

The distinction between JPEG and MJPEG is somewhat blurred at least as far
as AVI is concerned. So simply packing JPEG files into an AVI makes the
decoder think it's MJPEG.

> although i don't know what the mjpeg header should look like.

There is no standard MJPEG fileformat. There are some formats, which
carry MJPEG data like SMJPEG or the multipart JPEG you have (and some others
mainly used for Computer games). And AVI and Quicktime of course.

Burkhard

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