video broken on 1.75?

[Sameer Verma]

On Tue, Mar 19, 2013 at 5:32 PM, John Watlington <wad at laptop.org> wrote:
>
> When using a block transform based video codec (MPEG-1/2/4, H.263/4, etc)
> the dimensions of the video being encoded/decoded should always be a multiple
> of the block size (8x8 in the above cases, although for MPEG 16x16 should be
> used.)  To do otherwise requires serious contortions of the codec and doesn't
> reduce the processing load.  I'm not at all surprised that a hardware
> encoder/decoder would just fail.
>
> Cheers,
> wad
>
> On Mar 19, 2013, at 3:37 PM, Daniel Drake wrote:
>
>> On Mon, Mar 18, 2013 at 7:37 PM, Sameer Verma <sverma at sfsu.edu> wrote:
>>> We have a bunch of XO 1.75 going to Madagascar. These have build
>>> 13.1.0 (candidate 35). This ogv file [1] works well on a XO-1 but does
>>> not play via jukebox. The ogv file plays well in Browse (trouble with
>>> going fullscreen). It plays ok for a few seconds via MediaPlayer in
>>> GNOME.
>>>
>>> [1] http://verma.sfsu.edu/projects/olpc/sample-for-xo.ogv
>>
>> Thanks for reporting.
>> Unfortunately there are many ogg theora files that don't play back on
>> XO-1.75, but they normally fail with an error message:
>> http://dev.laptop.org/ticket/12004
>>
>> So I filed a new ticket for this video: http://dev.laptop.org/ticket/12634
>>
>> The reason that it works in Browse is probably that it is not using
>> hardware accelerated playback there.
>>
>> When I saw a case of #12004 before, I worked around it by re-encoding
>> the video as it had some slightly special parameters. This video would
>> appear to be similar. It is a 320x180 video somehow encoded into the
>> 320x192 theora resolution. I suspect if you re-encode it so that both
>> measurements are equal, it will work OK.
>>
>> Daniel
>> _______________________________________________
>> Devel mailing list
>> Devel at lists.laptop.org
>> http://lists.laptop.org/listinfo/devel
>
>
>

Interesting.

I got the source from TED as a MP4 wrapper.
http://video.ted.com/talk/podcast/2009/None/RennyGleeson_2009-light.mp4

Video: H.264 320x180
Audio: MPEG4-AAC

Converting that to Ogg Video using ffmpeg2theora

ffmpeg2theora -v 6 RennyGleeson_2009-light.mp4

gives me:

Video: Theora 320x180
Audio: Vorbis

This is what MediaPlayer tells me.

Looking at codec info via VLC tells me that the resolution is 320x180
but Display Resolution is 320x192
I don't know enough about this to know the difference. How should I
got about encoding the MP4 differently?

BTW, it works fine on a XO-1. Is that because it only does software
decoding on the XO-1?

cheers,
Sameer