Premiere Pro 2020 14.3.1 Export Bug - H.264 export with PSP or iPod Multiplexer results in file locked to 30 fps with audio out of sync
When exporting from Premiere using H.264 with Hardware Encoding, and changing the Multiplexer "stream compatibility" setting from "Standard" to either "PSP" or "iPod", the exported file is always interpreted as 30 fps, no matter the frame rate of the source or output target. This results in a different video playback speed for exports with the output frame rate set to anything other than 30 fps. For instance, if the intended output frame rate is 60 fps, then the exported file will play back at half the speed (30 fps), and if the output is set to 15 fps, it will play back twice as fast. The audio speed remains unchanged, and thus will drift out of sync with the video.
iMac 27" 2017
Display: Retina 5K
CPU: 4.2 GHz i7
RAM: 32GB 2400 MHz DDR 4
Graphics: Radeon Pro 580 8192 MB
OS: High Sierra 10.13.6
Premiere Pro 2020 version: 14.3.1
Previously, I was using the initial release of Premiere Pro 2020 (version 14.0, November 2019), and had not encountered this bug on that version. Since I upgraded from that version straight to version 14.3.1, June 2020, it is unknown to me at what point this bug was introduced.
Specifically, importing the exported files back into Premiere reports "PSP" exported frame rates as 30.00 fps, and "iPod" exports as 30.01 fps (see screenshot).
This behavior only seems to happen when using Hardware Encoding (under Video -> Encoding Settings) in conjunction with PSP or iPod Multiplexer stream compatibility. If Software Encoding is selected, the exported file plays back at the proper speed and frame rate. On my set up, selecting either CBR or VBR, 2 pass bitrate encoding only allows for Software Encoding (if I try to select Hardware Encoding when CBR or VBR, 2 pass is selected, I get the error "Your system's hardware does not support hardware acceleration for the current settings"). Therefore, I can only use Hardware Encoding with VBR, 1 pass bitrate encoding. Likewise, I can only select Hardware Encoding if "Export Audio" is checked. Thus, I can only reproduce the frame rate bug when encoding with VBR, 1 pass, since that's the only bitrate setting that allows for Hardware Encoding. Profile and Level settings don't make a difference, nor does the Target Bitrate setting. It doesn't matter whether the renderer is set to Metal or OpenCL either.
The screenshots show the Multiplexer "stream compatibility" setting, along with the exported files re-imported into Premiere, along with their reported frame rates (the "ms-hb.mp4" files refer to files exported with the "Match Source - High Bitrate" encoding preset and have the correct intended frame rate, "psp.mp4" refers to exports with the Multiplexer stream compatibility changed to "PSP", and the "ipod.mp4" files are the ones with the Multiplexer stream compatibility changed to "iPod". All files are encoded in H.264 with Hardware Encoding using VBR, 1 pass encoding).
Sean McNally commented
Seems to be fixed