On Tuesday 11 July 2006 23:48, Benjamin Zores wrote:
> Hi guys,
>
> I'm pretty new to this list so excuse me if questions have already
> been asked for. I'm an MPlayer developer and I recently did a few
> work to support ivtv cards under our player.
>
> First thing was a new pvr:// input that should be able to use
> V4L2/IVTV ioctl() to read from ivtv cards with no more needs to
> ivtvctl (at least for most common options).
>
> Anyhow, i'm currently working on a video output driver.
> I based my work on the old patch for MPlayer 1.0pre7 that was in
> misc/ from your SVN. It's now nearly integrated but i still have a
> few issues.
>
> 1. Does ivtv cards have audio output or just video (tv-out) ?
>
> Currently i'm sending MPEG-PES video data to the card but i wanted to
> know if i can do the same for MPEG-PES audio data.
The MPEG output does both audio and video. You must feed it a MPEG-2
program stream. The audio comes from the PVR card, not from the audio
card. Trying to feed it only video and doing audio with ALSA won't work
(impossible to guarantee A/V sync).
>
> 2. I do have a problem with decoder filling.
>
> It seems from my tests that the decode needs something like 80 MPEG
> frames before being able to display a single picture. As a result,
> MPlayer renders a stream with desyncronized A-V.
>
> >From MPlayer view, audio and video packets are synced but the
> > problem is that audio packets are played immediately when decoded
> > while video packets are displayed with a 80 frames delay.
>
> Is there then a way for ivtv decoder to start displaying received
> frames immediately ? Otherwise, is there any way to known the exact
> moment where buffer gets filled (and so, the exact time where
> pictures will be displayed) in order to delay audio packets from the
> same amount of time.
Feeding the pvr card a program stream will solve all these problems.
> 3. Is there some place where all of the IVTV ioctl() are described ?
> (something more than just ivtv.h)
No. Please be aware that the MPEG encoding API changed to a new v4l2 API
starting with kernel 2.6.18 (it will be in ivtv-0.8). Also note that
the ivtv decoding API will also change in 2.6.19 or .20 to a standard
v4l2 API. This as part of the effort to move ivtv into the kernel.
Hans
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