(2017-08-30 14:56)popcornmix Wrote:
(2017-08-29 19:49)amediauser Wrote: Player settings > Videos > Adjust display refresh rate > On start / stop
System settings > Audio > Allow passthrough > On
System settings > Audio > - Enable Dolby Digital (AC3) transcoding > On
Tested again with the follwing additional changes.
Player settings > Videos > Sync playback to display > On
System settings > Audio > PLL adjustment to maintain audio/video sync > Low
Can you just clarify with which settings out-of-sync audio occurs?
(i.e. default, with ac3 transcoding enable, and with PLL sync?)
Hi @popcornmix, thank you for taking a look at this.
The out of sync error occurs when using the combination "Allow passthrough", "Dolby Digital (AC3) capable receivers" and "Enable Dolby Digital (AC3) transcoding".
It is a little random, most of the time it will start in sync, but not always. As described previously, skipping around in the sample file will easily trigger it to go out of sync.
Once out of sync not even pausing will correct it.
When playing native AC3 in sync I see this lines like this in the debug log.
DEBUG: ProcessPacket - audio:98 video:99
When playing transcoded DTS in sync I see this in the debug log, there is a larger gap between audio and video.
DEBUG: ProcessPacket - audio:96 video:99
When playing transcoded DTS out of sync I see example such as these this in the debug log.
DEBUG: ProcessPacket - audio:99 video:94 < # Audio packets are ahead of video
DEBUG: ProcessPacket - audio:98 video:98 < # Audio video packets are the same
DEBUG: ProcessPacket - audio:95 video:99 < # Audio packets further behind video
The brief reversion to ffmpeg 3.1 didn't help, so its not down to that version bump.
When playing back stereo, native AC3 or disabling transcoding the sync remains fine.
The PLL option does not have have any effect on the problem, I only enable it as I believe it is now required for passthrough with "Sync playback to display" that I tested.