Audio syncing issue with H.264 exports

[retailgeek1]

Hi, I'm making some talking head YouTube videos in Premiere. Mostly talking head videos 10-20 mins long.

The source footage is recording on a blackmagic ATEM Mini Extreame ISO, so it's H.264 1080P 29.97 fps at around 25 mbit/sec.

All the audio and video is perfectly synced in my timeline and plays back fine. When I export with the high bit rate H.264 profile in Premiere (with match settings), the resulting file starts in sync but gets out of audio sync by the end of the file when played back on quicktime. However, the same output file stays in sync played through VLC.

If I output the same sequence with  med bit rate h.264 the video stays in sync when played in Quicktime and VLC.

Arguably, the problem is with Quicktime since the file plays in VLC, but Quicktime is so popular I hesitate to use a file that doesn't play well in it. Any tips or advice?

Is my problem with my source footage (do I need to transcode to an intermediate format)? Some alternative export settings? I'm pretty much a newby, so any tips are greatly apprecaited.

Thanks!

-Jason

[Ann Bens]

If the footage is variable framerate convert to constant framerate with Handbrake before bringing into Premiere.

[retailgeek1]

Thanks for the fast response. I actually didn't know that Framerate could be variable. My source footage is variable bitrate, but constant framerate 29.97. 

When you say variable framerate do you literally mean there are files that speed changes during a segment, or do you mean "fractional framerate" (ie 29.97 vs 30)?

[Ann Bens]

Post screenshot of clip in treeview using MediaInfo

[retailgeek1]

Source file from Blackmagic ATEM:

General
Complete name : /Volumes/Samsung T7/YT_RG_003/JG.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (iso4/avc1/isom)
File size : 4.59 GiB
Duration : 28 min 43 s
Overall bit rate mode : Variable
Overall bit rate : 22.9 Mb/s
Encoded date : UTC 2021-04-22 21:35:01
Tagged date : UTC 2021-04-22 21:35:01
Writing library : Apple QuickTime
com.blackmagic-design.camera.dateRecorde : 2021:04:22
com.blackmagic-design.camera.timelineID : 025366bb
com.apple.proapps.clipID : JG
com.apple.proapps.cameraName : 0
com.blackmagic-design.camera.uuid : 4CC7EEDCFA441408840DADE76B94640-0

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.1
Format settings : CABAC / 1 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 28 min 43 s
Bit rate : 22.7 Mb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.366
Stream size : 4.56 GiB (99%)
Language : English
Encoded date : UTC 2021-04-22 21:35:01
Tagged date : UTC 2021-04-22 21:35:01
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 3
Format : mp4a
Codec ID : mp4a
Duration : 28 min 43 s
Source duration : 28 min 43 s
Source_Duration_LastFrame : -11 ms
Bit rate mode : Variable
Bit rate : 128 kb/s
Stream size : 26.3 MiB (1%)
Source stream size : 26.3 MiB (1%)
Language : English
Encoded date : UTC 2021-04-22 21:35:01
Tagged date : UTC 2021-04-22 21:35:01

Other
ID : 2
Type : Time code
Format : QuickTime TC
Duration : 28 min 43 s
Frame rate : 29.970 (30000/1001) FPS
Time code of first frame : 16:35:01;00
Time code, striped : Yes
Language : English
Encoded date : UTC 2021-04-22 21:35:01
Tagged date : UTC 2021-04-22 21:35:01

Output from premiere using YouTube high setting (plays fine in VLC, and when uploaded to YouTube, but loses sync over time on Quicktime):

General
Complete name : /Volumes/Samsung T7/YT_RG_003/JG_1.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (mp42/mp41)
File size : 1.13 GiB
Duration : 23 min 46 s
Overall bit rate mode : Variable
Overall bit rate : 6 784 kb/s
Encoded date : UTC 2021-04-24 13:04:39
Tagged date : UTC 2021-04-24 13:15:23
TIM : 00;00;00;00
TSC : 30000
TSZ : 1001

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings : CABAC / 2 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 2 frames
Format settings, GOP : M=2, N=59
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 23 min 46 s
Bit rate mode : Variable
Bit rate : 6 457 kb/s
Maximum bit rate : 768 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.104
Stream size : 1.07 GiB (95%)
Language : English
Encoded date : UTC 2021-04-24 13:04:39
Tagged date : UTC 2021-04-24 13:04:39
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 23 min 46 s
Source duration : 23 min 46 s
Bit rate mode : Variable
Bit rate : 317 kb/s
Maximum bit rate : 460 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 54.0 MiB (5%)
Source stream size : 54.0 MiB (5%)
Language : English
Encoded date : UTC 2021-04-24 13:04:39
Tagged date : UTC 2021-04-24 13:04:39

H.264 Medium profile from Premiere (plays fine in Quicktime w/ no sync issues)

General
Complete name : /Volumes/Samsung T7/YT_RG_003/YT_RG_003_med.mp4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (mp42/mp41)
File size : 440 MiB
Duration : 23 min 46 s
Overall bit rate mode : Variable
Overall bit rate : 2 591 kb/s
Encoded date : UTC 2021-04-24 13:30:59
Tagged date : UTC 2021-04-24 13:40:31
TIM : 00;00;00;00
TSC : 30000
TSZ : 1001

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4.1
Format settings : CABAC / 2 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 2 frames
Format settings, GOP : M=2, N=59
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 23 min 46 s
Bit rate mode : Variable
Bit rate : 2 392 kb/s
Maximum bit rate : 768 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 29.970 (30000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.038
Stream size : 407 MiB (92%)
Language : English
Encoded date : UTC 2021-04-24 13:30:59
Tagged date : UTC 2021-04-24 13:30:59
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 23 min 46 s
Source duration : 23 min 46 s
Bit rate mode : Variable
Bit rate : 192 kb/s
Maximum bit rate : 299 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 32.2 MiB (7%)
Source stream size : 32.2 MiB (7%)
Language : English
Encoded date : UTC 2021-04-24 13:31:00
Tagged date : UTC 2021-04-24 13:31:00