Linux workflow for Android recorded videos

I just recently purchased DaVinci Resolve Studio for the H264/H265 support on linux. Unfortunately videos recorded from android are my main source and use the aac codec for audio which isn't supported. While this isn't ideal, at least transcoding the audio is far less time/resource consuming than transcoding the video so I am going to try and work with it.

I imagine there are several options but one quick option would seem to be:

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ffmpeg -i input.mp4 -vcodec copy -acodec ac3 output.mp4

This performs exactly the same as importing the original file (with aac audio) in that it imports an audio track but the audio track has no sound.

Another option which seemed promising was

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ffmpeg -i input.mp4 -vcodec copy -acodec flac output.mp4

This is a bit weird in that VLC plays the file with audio but just black video. However Resolve lets me import the video and seems to have video info/preview in the media view but Resolve crashes when adding to the timeline.

Another option was:

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ffmpeg -i input.mp4 -vcodec copy -acodec mp3 output.mp4

Similar to the flac, this plays in VLC with audio and a black video. But when imported into Resolve, it can be added to the timeline. The video seems to function but, like the file with ac3 audio, the audio track that imports has no sound.

I have had some partial success just by exporting the audio to a .mp3 file and adding that as a 2nd audio track. This works when exporting using the H264 Master preset but when using the Youtube preset, there is no sound. In addition, I'd prefer not to have to deal with separate audio and video files.

Can I get some guidance on how I might transcode the audio part of the file without re-encoding the video while maintaining a single file where the audio works in Resolve?

You could try wrapping it in a mov container and changing the audio to pcm:

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ffmpeg -i input.mp4 -c:v copy -c:a pcm_s24le -ar 48000 -ac 2 output.mov

This is how I do it:
viewtopic.php?f=21&t=200041#p1040419

You could try wrapping it in a mov container and changing the audio to pcm:

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ffmpeg -i input.mp4 -c:v copy -c:a pcm_s24le -ar 48000 -ac 2 output.mov

This seems to work, thanks for the reference and help!

Unfortunately now it's locking up when switching to the deliver tab. I don't know what happened since I haven't run any updates or made any changes since I got it working over the weekend. Time to troubleshoot new issue. Thanks again for the help.