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IDProjectCategoryView StatusDate SubmittedLast Update
0002862DCP-o-maticBugspublic2024-09-07 20:472024-09-11 01:06
Reporterfredmaher Assigned Tocarl  
PrioritynormalSeveritymajorReproducibilityalways
Status assignedResolutionopen 
Platform64 bitOSLinuxOS VersionUbuntu
Product Version2.16.90 
Summary0002862: Constant playback audio/video sync error with in-sync DCP
Description

Actallly 2.16.91 git e96f917d51
Audio is out of sync (late by about a frame) when playing back content in DCP-o-matic or playing back a DCP with DCP-o-matic Player.
But when the DCP is ingested and played out, it is in sync.

Steps To Reproduce

This is my input content:
eneral
Complete name : /home/fredmaher/Desktop/Purple_5-1.mov
Format : MPEG-4
Format profile : QuickTime
Codec ID : qt 0000.02 (qt )
File size : 7.15 GiB
Duration : 6 min 15 s
Overall bit rate mode : Variable
Overall bit rate : 163 Mb/s
Frame rate : 24.000 FPS
Encoded date : 2024-09-06 20:10:15 UTC
Tagged date : 2024-09-06 20:10:15 UTC
Writing application : Blackmagic Design DaVinci Resolve
Writing library : Apple QuickTime

Video
ID : 1
Format : ProRes
Format version : Version 0
Format profile : 422 HQ
Codec ID : apch
Duration : 6 min 15 s
Bit rate mode : Variable
Bit rate : 157 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 24.000 FPS
Color space : YUV
Chroma subsampling : 4:2:2
Scan type : Progressive
Bits/(Pixel*Frame) : 3.146
Stream size : 6.84 GiB (96%)
Writing library : Apple
Encoded date : 2024-09-06 20:10:15 UTC
Tagged date : 2024-09-06 20:10:15 UTC
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2
Format : PCM
Format settings : Little / Signed
Codec ID : lpcm
Duration : 6 min 15 s
Bit rate mode : Constant
Bit rate : 6 912 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Bit depth : 24 bits
Stream size : 309 MiB (4%)
Default : Yes
Alternate group : 1
Encoded date : 2024-09-06 20:10:15 UTC
Tagged date : 2024-09-06 20:10:15 UTC

Other
ID : 3
Type : Time code
Format : QuickTime TC
Duration : 6 min 15 s
Frame rate : 24.000 FPS
Time code of first frame : 01:00:00:00
Time code of last frame : 01:06:15:11
Time code, stripped : Yes
Language : English
Encoded date : 2024-09-06 20:10:15 UTC
Tagged date : 2024-09-06 20:10:15 UTC

Additional Information

I'm using a "professional" USB audio interface: Audient iD4

OS:
Distributor ID: Ubuntu
Description: Ubuntu 24.04.1 LTS
Release: 24.04
Codename: noble

Tagssync
Branch
Estimated weeks required
Estimated work requiredUndecided

Activities

carl

2024-09-10 00:59

administrator   ~0006533

Hey, if you look in the "Sound" tab of DCP-o-matic preferences, does it say "Play sound via PulseAudio", or something different?

fredmaher

2024-09-10 02:50

reporter   ~0006534

It says "PulseAudio". Also, something that may be helpful to know is that if I play the source content on my
ubuntu system (the same system I'm running DCP-O-MATIC) using VLC, it is in sync.

carl

2024-09-11 00:18

administrator   ~0006535

@carl some cleanups on 2862-latency but I'm guessing that pa somehow mis-reports latency. VLC has some comments about pa_stream_get_latency() not working in vlcpulse.c

carl

2024-09-11 00:56

administrator   ~0006536

Last edited: 2024-09-11 01:06

@carl also more-abstract{,2} branch for moving some more RtAudio-specific stuff behind AudioBackend

Issue History

Date Modified Username Field Change
2024-09-07 20:47 fredmaher New Issue
2024-09-07 20:47 fredmaher Tag Attached: sync
2024-09-09 15:55 carl Status new => acknowledged
2024-09-09 15:55 carl Summary sync issue => Constant playback audio/vido sync error with in-sync DCP
2024-09-09 15:55 carl Estimated work required => Undecided
2024-09-09 15:59 carl Summary Constant playback audio/vido sync error with in-sync DCP => Constant playback audio/video sync error with in-sync DCP
2024-09-10 00:59 carl Assigned To => carl
2024-09-10 00:59 carl Status acknowledged => feedback
2024-09-10 00:59 carl Note Added: 0006533
2024-09-10 02:50 fredmaher Note Added: 0006534
2024-09-10 02:50 fredmaher Status feedback => assigned
2024-09-11 00:18 carl Note Added: 0006535
2024-09-11 00:56 carl Note Added: 0006536
2024-09-11 01:06 carl Note Edited: 0006536