On Mon, 2008-11-10 at 23:00 +0100, Hans Verkuil wrote: > On Monday 10 November 2008 09:24:44 Alexander Pipelka wrote: > > Hi, > > > > Are there any news on the B-Frame issue. > > I sent a status log ~ 3 weeks ago. > > Hi Alex, > > I looked at it today and I could reproduce it. I also found what the > difference is between the old and current ivtv driver. When you pass > the B-frames to the card the API says that you should pass B+frames + 1 > to the card. So if there are 0 B-frames, then the number should be 0+1 > = 1. However, for some reason that does not seem to work for a > cx2584x-based card. If I put in 0 instead of 1, then it works again. > > What I don't know is if that really produces a stream without B-frames. > Applying the attached patch should fix the problem you have, but I > wonder if you can also test the presence of B/I/P frames and check that > you get the right results (i.e. really 0 B-frames). I can also test it, > but not easily and not until after two weeks from now. >
Tested the patch on a PVR-150 MCE. Here are the observations: B-frames requested B-frames got Remark ------------------------------------------------------------- 0 1 Plays normally 1 1 Plays normally 2 2 Plays normally 3 3 Choppy 4 4 Choppy and plays at faster speed So in conclusion: the patch did something but not quite what it was expected to. At least now with B-frames set to 0 it does save a stream which however has not 0 but 1 B-frame per P frame. At the higher B-frame ratios, the video is unusable due to choppiness and/or faster replay speeds (GOP at 12 frames except at 4 B-frames where it was set to 15 by qv4l2). The audio seemed normal though. Levente _______________________________________________ ivtv-users mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-users
