2015-05-31, 02:36
I'm running OpenELEC 5.0.8 on a Raspberry Pi 2, with a recent model Sony home theater projector and audio passthrough over an ALSA TOSLINK board (dtoverlay=hifiberry-digi). I have been running with Adjust Display Refresh Rate enabled, and Sync Playback to Display disabled.
Every so often (maybe once or twice per hour), video stutters badly and continuously for several seconds. Audio remains fine, but it looks as though a lot of video frames are being dropped. Eventually, it corrects itself. The codecinfo display's drop/skip count doesn't noticeably increase when this happens, but I do notice the W(fps) number changing a lot. I see entries like this in kodi's log file around the same time:
01:31:21 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6422020534.921498, should be:6422030571.303475, error:10036.381977
01:33:19 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6540470514.043476, should be:6540480771.523143, error:10257.479667
01:35:18 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6658970708.945143, should be:6658980832.653199, error:10123.708056
This happens with both 720p and 1080p files, regardless of whether the file is being read from a USB drive or the network, and regardless of the cache settings I use in advancedsettings.xml. Disabling omxplayer doesn't help (and I wouldn't expect it to, since codecinfo always shows the mmal decoder in use). I have only tested with 23.976 fps h.264 encodings.
Very recently, I tried enabling Sync Playback to Display: PLL. After just a couple hours of use, I haven't seen the problem return with this setting enabled. I was under the impression that this setting was unnecessary with audio passthrough, and I'm pretty sure I didn't need it with my CuBox i4pro. I don't even know exactly what it does, since the PLL setting isn't explained on the wiki.
Is this a known problem? Is the PLL sync method a reliable fix? What does it do?
Every so often (maybe once or twice per hour), video stutters badly and continuously for several seconds. Audio remains fine, but it looks as though a lot of video frames are being dropped. Eventually, it corrects itself. The codecinfo display's drop/skip count doesn't noticeably increase when this happens, but I do notice the W(fps) number changing a lot. I see entries like this in kodi's log file around the same time:
01:31:21 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6422020534.921498, should be:6422030571.303475, error:10036.381977
01:33:19 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6540470514.043476, should be:6540480771.523143, error:10257.479667
01:35:18 T:1587987520 DEBUG: CDVDClock:iscontinuity - CDVDPlayerAudio::HandleSyncError2 - was:6658970708.945143, should be:6658980832.653199, error:10123.708056
This happens with both 720p and 1080p files, regardless of whether the file is being read from a USB drive or the network, and regardless of the cache settings I use in advancedsettings.xml. Disabling omxplayer doesn't help (and I wouldn't expect it to, since codecinfo always shows the mmal decoder in use). I have only tested with 23.976 fps h.264 encodings.
Very recently, I tried enabling Sync Playback to Display: PLL. After just a couple hours of use, I haven't seen the problem return with this setting enabled. I was under the impression that this setting was unnecessary with audio passthrough, and I'm pretty sure I didn't need it with my CuBox i4pro. I don't even know exactly what it does, since the PLL setting isn't explained on the wiki.
Is this a known problem? Is the PLL sync method a reliable fix? What does it do?