On Wednesday, May 18, 2011 06:10:43 Bhupesh SHARMA wrote: > Hi, > > (adding alsa mailing list in cc) > > > On Thursday, May 12, 2011 18:59:33 Charlie X. Liu wrote: > > > Which HDMI receiver chip? > > > > Indeed, that's my question as well :-) > > We use Sil 9135 receiver chip which is provided by Silicon Image. > Please see details here: http://www.siliconimage.com/products/product.aspx?pid=109 > > > Anyway, this question comes up regularly. V4L2 provides timestamps for > > each > > frame, so that's no problem. But my understanding is that ALSA does not > > give > > you timestamps, so if there are processing delays between audio and > > video, then > > you have no way of knowing. The obvious solution is to talk to the ALSA > > people > > to see if some sort of timestamping is possible, but nobody has done > > that. > > I am aware of the time stamping feature provided by V4L2, but I am also > not sure whether the same feature is supported by ALSA. I have included > alsa-mailing list also in copy of this mail. Let's see if we can get > some sort of confirmation on this from them. > > > This is either because everyone that needs it hacks around it instead > > of trying > > to really solve it, or because it is never a problem in practice. > > What should be the proper solution according to you to solve this issue. > Do we require a Audio-Video Bridge kind of utility/mechanism? I don't believe so. All you need is reliable time stamping for your audio and video streams. That's enough for userspace to detect AV sync issues. Regards, Hans > > Regards, > Bhupesh > > > > > > > > > -----Original Message----- > > > From: linux-media-owner@xxxxxxxxxxxxxxx > > > [mailto:linux-media-owner@xxxxxxxxxxxxxxx] On Behalf Of Bhupesh > > SHARMA > > > Sent: Wednesday, May 11, 2011 10:49 PM > > > To: linux-media@xxxxxxxxxxxxxxx > > > Cc: Laurent Pinchart; Guennadi Liakhovetski; Hans Verkuil > > > Subject: Audio Video synchronization for data received from a HDMI > > receiver > > > chip > > > > > > Hi Linux media folks, > > > > > > We are considering putting an advanced HDMI receiver chip on our SoC, > > > to allow reception of HDMI audio and video. The chip receives HDMI > > data > > > from a host like a set-up box or DVD player. It provides a video data > > > interface > > > and SPDIF/I2S audio data interface. > > > > > > We plan to support the HDMI video using the V4L2 framework and the > > HDMI > > > audio using ALSA framework. > > > > > > Now, what seems to be intriguing us is how the audio-video > > synchronization > > > will be maintained? Will a separate bridging entity required to > > ensure the > > > same > > > or whether this can be left upon a user space application like > > mplayer or > > > gstreamer. > > > > > > Also is there a existing interface between the V4L2 and ALSA > > frameworks and > > > the same > > > can be used in our design? > > > > > > Regards, > > > Bhupesh > > > ST Microelectronics > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux- > > media" in > > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-media" > > in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > > > > > -- > > regards > > Shiraz Hashim > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
