[Ffmpeg-devel] [PATCH] MJPEG wrongly displayed with vertical YUV422

[Eric Piel]

31.07.2006 15:15, Michael Niedermayer wrote/a ?crit:
> Hi
> 
> On Mon, Jul 31, 2006 at 11:05:26AM +0200, Diego Biurrun wrote:
>> Hmmm, it seems that this one slipped through the cracks ...
>>
>> On Sun, May 28, 2006 at 12:20:00AM +0200, Eric Piel wrote:
>>> (please CC: me as I'm not subscribed to this mailing list)
>>>
>>> ffmpeg doesn't handle the mjpeg files with a "vertical" YUV422. Here is 
>>> an example:
>>> * A fine video: http://pieleric.free.fr/ffmpeg/sevilla-mjpeg-yuv422h.avi 
>>> (directly from my camera)
>>> * Mostly same video which "ffplay" displays with wrong colors: 
>>> http://pieleric.free.fr/ffmpeg/sevilla-mjpeg-yuv422v.avi (lossless 
>>> rotation of the previous file)
>>> (both files are 9 Mb)
>>>
>>> Actually there is even a comment in mjpeg.c which explains the problem : 
>>> /* XXX: not complete test ! */
>>>
>>> The test "switch((s->h_count[0] << 4) | s->v_count[0]) {" needs to also 
>>> handle 0x12. Like 0x21, it's also YUV422 but this one is "vertical". The 
>>> problem is that there is currently no PIX_FMT_* in ffmpeg which 
>>> corresponds to this coding. So here is a patch (against SVN 5414) to add 
>>> the support for this format. It adds the types PIX_FMT_YUV422VP and 
>>> PIX_FMT_YUVJ422VP. With this patch I can correctly display both videos :-)
>>>
>>> Let me know if that's the right way to fix the bug. Also, I've added 
>>> PIX_FMT_YUV*422VP to the minimum of places as possible, maybe I forgot 
>>> some places...
>> Just checked the patch, it works as advertised ...
> 
> PIX_FMT_YUVJ422VP is unaceptable, it should be called PIX_FMT_YUVJ440P
Here is attached a corrected patch which fix the naming. Sorry, I had 
tried to find the real naming but without success... those names are 
quite a mess for me.


> and such vertical subsampled format can pretty much only occur
> if you rotate 4:2:2 video, should we really support that? what about
> rotated interlaced video?
Well, every tool which support JPEG seems to support this format, so why 
not ffmpeg? IMHO, even if it is not so much used, the simple fact that 
it allows to display lossless rotated video is worthy. Adding support 
for it in ffmpeg is rather simple (especially since the patch is just 
there ;-) ).

Please apply,
Eric

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