why Virtualdub don't open mjpeg of ffmpeg?

[marcorocchini]

Hi

considering my source https://dl.dropboxusercontent.com/u/39871584/C0020.mxf

I use ffmpeg to:

ffmpeg -i c0020.mxf -vcodec mjpeg -pix_fmt yuv422p -q:v 0 -an output.avi

convert .mxf in mjpeg

But when I try to open it in virtualdub I get this error:


[Attachment 24636 - Click to enlarge]

multiple chroma blocks not supported.


Can I enhance the encoding in FFMPEG so virtualdub can open output.avi correctly, of course keeping the mjpeg encoding ?

thanks

ps. to decompress, in virtualdub, I use the internal decompressor (option, pref., avi-->prefer internal decoders)
please I like to use internal mjpeg decompressor, not other decompressor

[jagabo]

I used your command line on the same source file. VirtualDub had no problem opening the AVI. ffmpeg was used to decode it.



I suspect VirtualDub's internal MJPEG decoder doesn't support YUV 4:2:2.

[poisondeathray]

Why do you want to use internal mjpeg decoder ?

[poisondeathray]

I suspect VirtualDub's internal MJPEG decoder doesn't support YUV 4:2:2.

Seems to decode ok with other MJPEG encoders, eg.. picvideo at 4:2:2


marcorocchini - this doesn't affect results of vdub's internal decoder, but you can increase ffmpeg's mjpeg encoding quality by locking the min/max quantizers . If you don't specify min/max, the quantizer will still be variable

-q:v 1 -qmin 1 -qmax 1

[marcorocchini]

mmmmmmmmmmmmmmmmmmmmmmmmmmmm interesting. Absolute interesting.

the -q:v 1 -qmin 1 -qmax 1 to increase quality.

However it's strange that virtualdub can not decode with internal mjpeg decoder, wich means "multiple chroma blocks not supported" ?

In effects does not seems a problem of 422, because ohters encoding (eg picvideo) in 422 are well opened by virtualdub. This problem is specific of the ffmpeg mjpeg. I have try to encode in mjpeg with virtualdub using the FFdshow mjpg and the risults is the same of the ffmpeg encoding ... what a terrible thing