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NextLevel / NextLevelSessionExporter

🔄 Export and transcode media in Swift
http://nextlevel.engineering
MIT License
262 stars 49 forks source link

Exported videos missing video track (audio only) #38

Open GrandPoohBear opened 2 years ago

GrandPoohBear commented 2 years ago

In some cases, we have seen videos that are exported by NextLevelSessionExporter that seem to consistently drop the video tracks entirely, leaving just an audio track in the output file. Luckily, it's fairly easy to detect the problem - looking at the ratio of file sizes between compressed and uncompressed files leaves completely silly compression ratios.

We're working on getting a reliable repro case, but it's possible it has something to do with videos that came from Snapchat.

When I know more, I can post back, but wondering if others have seen anything similar, and if there's a way to prevent it from happening?

dac09 commented 2 years ago

Hi @GrandPoohBear did you find the root cause for this by any chance?

From our observations, we are seeing this happening on x86/x64 (we're building a universal binary) - but not on m1 macs.

I wonder if this might help you narrow down the cause.

GrandPoohBear commented 2 years ago

Interesting color, but no, unfortunately! We're seeing it on iOS. It will happen consistently with one of our testers with one source movie on one device, but haven't even been able to repro with the same source on other devices, or other similar sources on the same device 🤷🏻‍♂️