premiere pro shows a wave form and plays audio for an MP4 file via audio channels preview but will n

[bobw111]

I have an MP4 clip on my timeline that PRP shows an audio waveform for.  When I play that clip in the timeline no audio is played.  However, if I right click on the clip, select Audio Channels, select "Left" in the Preview Media Source Channel, and click on the play arrow, the audio for that channel plays properly.  The right channel was never intended to have sound so no surprise it doesn't play.  I've used MP4 clips from this camera with no issues for the last 6 years, with this being the first clip this has ever happened to me on in PRPro.  I've tried using Media Encoder and converting the file to Prores 422 .mxf, and that file also has the same problem.  I opened the file in Audition and the same problem existed, but when I did an Edit/Extract files to mono the new mono audio tracks play fine.  However, when I right clicked on the file in the Files panel in Audition and selected Extract Audio to New File, the extracted stereo file has a waveform, but again there is no audio when I click the play button.   I'm including this in the PRPro forum because that is where I first discovered the problem.

[Sumeet Kumar Choubey]

Hi bobw111,

We're sorry to hear about this. Please let us know the version of Premiere Pro that you are using. Also, is this happening with any specific media or all of them? If possible, please share a download link for one of the sample media with which you are experiencing this issue. It will help us to diagnose the issue properly.

Thanks,

Sumeet

[bobw111]

PR Pro 25.2.1.  So far it has only happened to one file that I uploaded today.  The first 30 seconds of the file are being attached below.

[Sumeet Kumar Choubey]

Thanks for the sample media. The audio playback seems to be working fine at our end. Have you tried checking if the audio playback works in the Source monitor? Also, while playing in the timeline, if you don't see any activity in the audio meters, please check if the Track Volume for the Mix track is muted by chance.

-Sumeet

[bobw111]

I see activity in the audio meters, just no sound coming out.  I'll have to check again, but if I remember correctly, there was no audio playback in the source monitor either.  I'll let you know just as soon as the 5 hour of video I just added to this same sequence finish generating peak files.  FWIW, only had 2 hours of video when this issue occurred, and only on this one file.

[bobw111]

OK, the problem has popped up in additional clips, and there is one thing common to all the clips.  They all have stereo audio tracks, but a microphone was only input to one of the two tracks.  None of the clips play audio in the source window despite having activity showing in the audio meters.  None of the clips will play audio in the timeline.  All of the clips will play audio during audio preview under Audio Channels.

[bobw111]

OK, this gets weirder.  First, VLC plays the audio fine on all clips, but VLC audio deaults to track 1 so no surprise I guess.  Second, If I connect earphones in either jack on the front or back of the computer, the audio plays fine on all clips.  FTR my headphones are Beyerdynamic DT 770 Pros and definitely stereo.  But if I plug my speakers into the earphone jack on either the front or back of the computer then the problem exists.  Steps I've taken to remedy the issue.  First, I went into the Device manager and uninstalled ALL extraneous hidden devices under "Sound, video, and game controllers".  Then I deleted the realtek audio driver, downloaded the correct driver from Dell for my system, rebooted, and ran the driver install.  The install process did an uninstall of the Realtek audio driver, rebooted, then installed the audio driver. After that I did another reboot.  At which point I went to open PrPro from my taskbar and got a "File doesn't exist" error.  Turned out Premiere Pro 25.2.3 was installing at an inconvenient time.  However, after the update, the problem still existed after all these steps.  I then went in to Audio Channels for the problem clips and set selected the channel with audio as output for both channels.  Audio then played just fine on all clips.  So, at least I have a quick easy work around.  However, it would be nice if this just all worked like it should.

[Sumeet Kumar Choubey]

I'm glad you found a workaround! Just to confirm, in Pr, audio playback works while using headphones, but it doesn't work when you connect the speakers to the same audio jack, right? If so, can you please check if the left channel speakers are working properly or if the stereo balance is configured properly for the speakers? I suspect that might be the reason the workaround is effective, because it's basically copying and playing the same left channel on right channel speakers. 

Thanks,

Sumeet

[bobw111]

Sorry, I forgot to include that I had double checked that each channel worked properly on both the speakers and headphones, and that the stereo balance was properly configured for both devices.   And yes, the work around is effective precisely because it copies and playes the left channel through the right speaker.  It would still be nice if it all just worked properly.  I'll keep digging at this and let you know if I discover anything.  I suspect I might be the "canary in the coal mine" on this one and that the problem may pop up for more people in the future since I am working with a brand new computer with all freshly installed software.  It might be that there is a hardware/software issue that is just coming to light.