[MPlayer-dev-eng] MPlayer and raw video

[Mats Peterson]

On 02/25/2016 06:12 PM, Reimar Döffinger wrote:
> On Thu, Feb 25, 2016 at 08:13:25AM +0100, Mats Peterson wrote:
>> Since there for some reason hasn't been any response to my previous posting,
>> here we go again:
>
> Well, this list is for development and patches.
> Bug reports belong on either -users or the bug tracker.

Already filed.

>
>> MPlayer naively assumes that 'rawvideo' raw video from libavcodec (whether
>> it's contained in AVI, QuickTime or something else) contains 24-bit RGB
>> triplets.
>
> No, not really.
>

Yes it does. Check the error messages when playing the files. It will 
complain at the packet size being too small, which is clearly an 
indication that it thinks it should be 24-bit RGB when it is in fact 
something much less than that.


>> What's more, MPlayer misinterprets a negative height in the BITMAPINFOHEADER
>> for AVI files as being a very large unsigned value, rather than the
>> indication of the video data being arranged top-to-bottom rather than
>> bottom-to-top.
>
> My information is that negative values are very much not permitted
> in AVI, even though it usually works when things go through the VFW
> pipeline.
> It's also possible that uncompressed formats would allow it though.
> -demuxer lavf accepts it, but I don't think it works really properly
> either.
>

They are permitted. Read the Microsoft documentation on 
BITMAPINFOHEADER. And FFmpeg uses it correctly, since it stores the 
image data top-down for raw video.

>> The files below with raw video will play without video in MPlayer.
>
> There is (ok, rather was) simply no 2 bpp or 4 bpp support in MPlayer.
> The mov issue was a rather special case in part due to lavf not doing
> things in a way that is nice to us and our native demuxer not supporting
> those paletted raw formats at all.


I see. Does that mean you won't support in the future? FFplay plays 
these files just fine, so I don't see why MPlayer shouldn't be able to 
play this rudimentary type of video as well.