I have found that MP4 files exported from Apple Compressor (both 4.8 and 4.9) with "Allow export segmentation" checked ON are imported into Premiere Pro at 23.98 or 23.97 fps instead of 23.976 fps. This leads to duplicate and/or dropped frames within the Source Monitor and on the Program timeline.
I tried to modify > interpret footage > assume 23.967 fps – however duplicate and dropped frames persist.
This occurred in both...
- Adobe Premiere Pro version 24.6.3 (Build 4) and 25.0.0 (Build 61)
- macOS Sequoia 15.1 and 15.1.1
- Internal MacBook Pro Apple M2 Max (16-inch, 2023), 96 GB RAM, 2 TB SSD
- External Samsung Portable SSD T9, 2 TB connected via USB 3 cable
I found this issue by comparing MP4 exports that have timecode burn-in side-by-side against their source files.
Source files are video only (no audio) Apple ProRes 422 QuickTime files with running times ranging from 3 minutes to 1 hr 47 min.
NOTE: MP4 files exported from Apple Compressor with "Allow export segmentation" checked OFF imported into Premiere Pro at 23.976 fps as expected.
Imported MP4 file (exported with "Allow export segmentation" checked ON) details:
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/mp41/mp42)
File size : 5.25 GiB
Duration : 1 h 15 min
Overall bit rate : 9 997 kb/s
Frame rate : 23.976 FPS
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4
Format settings : 4 Ref Frames
Format settings, CABAC : No
Format settings, Reference frames : 4 frames
Format settings, GOP : M=2, N=15
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 h 15 min
Source duration : 1 h 15 min
Bit rate : 9 995 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Variable
Frame rate : 23.976 (23976/1000) FPS
Minimum frame rate : 7.992 FPS
Maximum frame rate : 23.976 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.201
Stream size : 5.25 GiB (100%)
Source stream size : 5.25 GiB (100%)
Title : Core Media Video
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC
Imported MP4 file (exported with "Allow export segmentation" checked OFF) details:
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42 (isom/mp41/mp42)
File size : 5.25 GiB
Duration : 1 h 15 min
Overall bit rate : 9 999 kb/s
Frame rate : 23.976 FPS
Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Main@L4
Format settings : 4 Ref Frames
Format settings, CABAC : No
Format settings, Reference frames : 4 frames
Format settings, GOP : M=2, N=15
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 h 15 min
Bit rate : 9 997 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.201
Stream size : 5.25 GiB (100%)
Title : Core Media Video
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC
Steps to reproduce:
- Export MP4 from Apple Compressor with settings...
- Import into Premiere Pro
Expected Result: Frame Rate to be 23.976 fps
Actual Result: Frame Rate is 23.98 fps
1 Pinned Reply
Hi @mikequinnjr - Thanks for submitting your bug report. This seems like a bug with Apple Compressor not Premiere Pro. If Compressor is segmenting the files while encoding and not putting them back together properly then I would agree that is a problem. It seems that by checking the box "Allow export segmentation" ON Compressor is creating a variable frame rate file while it is OFF it is constant.
In your interpret footage I would expect that to resolve your issue, but not if you are setting t
...
2
Replies
Hi @jamieclarke - Thank you for your response. Ha! Sorry, "23.967" was a typo on my part. Yes, I did try 23.976 and unfortunately the issue persists. Here are the steps I took...
Interpreted footage to 23.976
(Fig. 1)
In the project browser, Frame Rate has changed from 23.98 to 23.976 fps.
However, when verifying the assumed frame rate by reopening Modify > Interpret Footage....
It is revealed that the assumed frame rate is still 23.98
Additionally, this input field won't retain 23.976 as an input value.
Each time I enter 23.976 and then click outside of the input field the value reverts back to 23.98
Even though 23.976 is shown in the project browser.
(Fig. 2)
Checking the video file in both the source viewer and also by stacking it on top of the source file in a timeline reveals that dropped/duplicate frames persist even though the frame rates and durations match.
(Fig. 3)
However, timecode burn-in within the variable frame rate export file is frame accurate to the source file when played back in QuickTime Player, Final Cut Pro 11 and DaVinci Resolve 19, so it would seem that the frame rate/accuracy issue is more related to how Premiere Pro handles video files with variable frame rates and not Compressor related.
I agree, though, it is problematic that Compressor creates variable frame rate files with segmentation ON and constant frame rate files with it checked OFF without any notice to users, and so I will take that issue to Apple.
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