AV sync issues with new drivers analized.

[kapusta]

I've observed a very intersting thing about the A/V sync issues with the new drivers. From the looks of things when video and audio start plaing in sync, they play at 29.97 video frames per second. However something somewhere thinks that the video needs to be played at 30 frames per second. As a result from time to time there is a small glitch in video, where video is pushed forward with respect to the audio to "catch it up" with the suppossed 30 FPS speed. So while video is forced through micro glitches to play at 30 (even though it should be played at 29.97) the audio happily continues at 29.97. This can be clearly seen in the audio delay itself, which becomes 3.6 seconds per hour (about 1 second per 16.7 minutes of the program).

My guess is that somewhere in the code DVBLink tells the driver to play at 30 FPS. The old driver sees that it's incorrect and simply ignores it. The new driver tries to compensate for it by glitching. Another possibility is that the 30 FPS is the correct speed and AV is being played too slow at 29.97. Eventually the video buffer get's full and glitches. Since the audio takes so much less space, the audio continues at 29.97 since the audio buffer isn't full for a long time. Either way, it looks like a 30 vs 29.97 FPS issue.

Thanks!

[ceeps]

Yea I've experienced the issue you are describing. The audio and video start out relatively in sync and slowly the gap between audio and video grows.

[kapusta]

I've got rid of the issue. The 1.5.7 drivers fixed it. In order for the drivers to have full effect you have to reboot the computer and after it boots with new drivers, power cycle the HDPVRs. The reason is that the firmware file (hcwhdpvr.rom) is only loaded during power cycles. So you need to first upgrade the drivers and then have the box download the firmware.

[Braumin]

Have you had power cycle issues with the 1.5.7 driver? 1.0.3.5 has been rock solid for me, but I also have audio sync issues and don't want to fix audio at the expense of HDPVR crashes.

[kapusta]

Once in the past 10 days since I upgraded 10 days ago from 1.0.5.3. (I'm running two at the same time on the same machine so can I say once in 20 days or 1/2 in 10? )

[superdeef]

in my case the audio always comes first. It's the video that trails. The desync doesn't really grow, sometimes it's just worse. the 1.5.7 drivers did do a lot of good though.