Re: ps3 issues

["Zeeshan Ali (Khattak)" <zeenix gmail com>]

Hi Herique,

2009/6/10 Henrique Ferreiro García <henrique ferreiro gmail com>:
> Hi!
>
> I have a PS3 and the experience with Rygel isn't the best possible so
> far:

  Sad to hear. :(

> Transcoded videos are always resized to 640x480, even 720p media. I saw
> there are implemented two profiles: MPEG_TS_SD_US and MPEG_TS_HD_US,
> shouldn't the second one be selected is the original resolution exceeds
> SD resolution?

  I think thats more of a bug in PS3, it *should* do that. I guess it
just selects the first one that it can play. What we could do is to
put the HD resource first if original resolution exceeds SD
resolution.

> Also, couldn't the files be transcoded with theirs original resolution?
> I think that ps3 media server does that (at least the media doesn't
> appear resized)

   Well in theory yes but rygel identifies transcoding target by DLNA
profiles and these profiles are very specific (i-e SD, HD etc). Note
that this is just the simplest solution I went for and I wont be
against having non-DLNA profiles as transcoding targets if really
needed.

> Trying to be even more general, couldn't Rygel select which stream has
> to ben transcoded depending on the supported formats? This ps3 media
> server also does that. It seems a waste of computing power to transcode
> h264 and ac3 to mpeg2 when only remuxing to mpegts is necessary.

  That should be possible but we face the same problem i mentioned
above: identification of transcoding targets by DLNA profiles. At the
very least we should be easily able to avoid re-encoding to mpeg2 if
source stream is already in that format (this one is already on my
TODO).

> Other concern I have is the quality of the transcoded media. The files I
> tried were much worse when streamed. I think the gstreamer pipeline
> should be tuned to fix this. What is very strange related to this is
> that, when I tried to copy a file, it was very slow (300kbps approx.).
> If quality is so bad, I think this should go much faster.

   That is when transcoding to HD or SD? I noticed that with HD the
playback used to halt from time to time. I am yet to investigate for
the real cause of this but i also suspect the transcoding pipeline to
be slow.

   About quality, I really haven't noticed anything with HD but with
SD yes the quality is pretty low and I am not astonished since it is
being scaled up again on the PS3 to fit my 1366x768 screen.

> I have some other worries but I think for now these are enough. If you
> can guide me on some of these issues, I would love to help with fixing
> them.

   That would be great. You want to look at
src/rygel/rygel-*transcod*.vala . About the pipeline performance, I am
afraid you'll need to get your hands more dirty and fix the gstreamer
elements.

> Thanks in advance.

  No problem! By the way, please keep in mind that although PS3 is one
of the main targets, it is certainly not the only one (unlike for
ps3mediaserver) so all changes that improve PS3 support is welcome as
long as it doesn't break compatibility with other clients/renderers.

-- 
Regards,

Zeeshan Ali (Khattak)
FSF member#5124