[MPlayer-users] BUG: theora codec and bmovl filter

Michael auslands-kv at gmx.de
Mon Oct 5 13:43:02 CEST 2009


Well, yes theora works fine with many resolutions. Also in mplayer. The 
problem with the greenish lines at the top (most probably 8) only occurs 
when mplayer also uses the bmovl filter. So it is probably still a problem 
in mplayer/bmovl and not in theora, I guess.

But anyway, if one sticks to multiples of 16, bmovl works fine with theora. 
This is o.k. for me, although I would find it nice if bmovl also worked with 
other video resolutions.

Thanks

Michael

Giorgio wrote:

> Yes, it seems like the Theora codec works better when the video width
> and height multiples of 16. There is a very interesting book about
> theora at:
> 
> http://en.flossmanuals.net/theoracookbook
> 
> In this page http://en.flossmanuals.net/TheoraCookbook/EncodingIntro it
> says:
> 
> "Sometimes video source material does not make use of the full video
> frames, leaving black borders around the video. It is a good idea to
> remove black or otherwise unused parts from the video as this usually
> improves the quality and file size of the encoded Theora file. If
> possible, try to keep video width and height multiples of 16. The
> Theora format is capable of, but not very efficient at, storing video
> using other arbitrary frame sizes."
> 
> But anyway, as stated in http://wiki.xiph.org/Theora, it should be
> able to work fine with all dimensions:
> 
> "Features available in the Theora format (and a comparison to VP3 and
> MPEG-4 ASP):
> ...
> - non-multiple of 16 picture sizes (as possible in ASP, but not in VP3)
> ...
> "
> 
> 
> 2009/10/5 Michael <auslands-kv at gmx.de>:
>> Reimar Döffinger wrote:
>>
>>> On Mon, Oct 05, 2009 at 11:31:05AM +0200, Michael wrote:
>>>> I have a strange bug here. It only occurs if mplayer displays a theora
>>>> video and the bmovl filter is used. In this case the first eigth(?)
>>>> lines of the video show a greenish color.
>>>
>>> Is the resolution of your video maybe not a multiple of 8?
>>> AFAIK theora encodes videos upside-down, might be that bmov has an issue
>>> with that.
>>
>> Thanks, this was a good hint!
>>
>> Actually, there are no problems, if the video size is a multiple of 16!
>>
>> If I encode the videos in 720x400 it works also with the bmovl filter.
>>
>> Michael
>>
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