[Telepathy] H264 SVC ?

Sjoerd Simons sjoerd.simons at collabora.co.uk
Fri Oct 1 08:05:28 PDT 2010

On Fri, 2010-10-01 at 18:07 +0900, Yann wrote:
> Dear all,
> I observe that I get better audio/video results with Gtalk plugin than
> with Empathy 2.30.2 (on Lucid)

That's really non-specific. x264 was badly tune for video conferencing
using in Lucid, Maverick might be better

> Someone told me that it may be because Gtalk uses H264 SVC, and not Empathy.

Probably someone not really understanding what's going on :).. H264 SVC
doesn't actually result in better quality, it just makes it easier to
scale to the available bandwidth if you send the video to multiple
participants. For p2p it doesn't really help much as you can just change
what your encoder outputs there.

The reason the Gtalk webclient might have better quality is that they do
some quality enhancements on their audio streams (which is being worked
on for pulseaudio) and that they've tuned their h264 encoder better for
use with voip.. The last part is getting better with newer gstreamer
versions but it's partially a distribution question as it depends on
which exact h264 encoder you're using.

> As it is a norm, it could be possible to implement it in Telepathy,
> isn't it ? Is it planned or started or maybe already done ?

The fact that GTalk can use it doesn't make it a norm and the Telepathy
projects doesn't create video codecs. That's a question for the X264
project for example, but also it won't help you :)

Sjoerd Simons <sjoerd.simons at collabora.co.uk>
Collabora Ltd.

More information about the telepathy mailing list