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iPhone MP4 converted to Pro Res 422 out of sync
I have searched the forums and found this problem on many flavors of mp4, but no good solution thus far:
I have an mp4, recorded with an iPhone. Its 6 min 20 sec long, 1280×720, AAC, h.264, 29.643fps, 11.86Mbps, mono, 48kHz, 63 kbps. The mp4 is in sync.
I have attempted to convert it to Apple Pro Res in both Compressor (with and without frame control) and in Mpeg Streamclip. The resulting converted files play just fine in Quicktime Player 7. When I drop either of them into FCP (and say “yes” to changing sequence settings to match), the audio needs rendering. I render, then play the file. It’s in sync at the beginning and at least a full second out of sync by the end.
If I try to work with the video anyway, producing around the sync issues by layering in other video, effects, stills, etc – and using audio recorded from another source (aif) – once I render, the video slips!
Same thing happens if I convert to DV instead of Pro Res, but the DV file actually loses sync when playing in QT7 too!
How can I work around all this?
Thanks in advance.
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7 Replies
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[Louise Macaulay] “I have attempted to convert it to Apple Pro Res in both Compressor (with and without frame control) and in Mpeg Streamclip. The resulting converted files play just fine in Quicktime Player 7. When I drop either of them into FCP (and say “yes” to changing sequence settings to match), the audio needs rendering”
If you do a proper conversion, you shouldn’t need to render the audio.
Make sure is PCM 48Khz.
rafael -
Thank you for your response Rafael. I converted again, this time in Compressor, with Frame Control on, audio settings at Linear PCM, Stereo, 48kHz, Best render quality, 16 bit sample size. The audio no longer needs rendering when I drop it into FCP, but it still loses sync significantly. I’m making another conversion now with frame control off…. in the meantime, any other ideas? Thanks again.
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No idea about the sync Louis, but don’t bother with the “Frame Control”.
That only affects the picture processing.
rafael -
[Louise Macaulay] “I have an mp4, recorded with an iPhone. Its 6 min 20 sec long, 1280×720, AAC, h.264, 29.643fps, 11.86Mbps, mono, 48kHz, 63 kbps. The mp4 is in sync.”
29.643 fps? Where did you get that setting from?
This is me – this is what I do – https://web.mac.com/garymmw
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When I click “stream info” in Mpeg Streamclip it says the MP4 video track is 1280×720, ~29.642fps, 11.86 Mbps.
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Hi there,
I just came across a similar problem to yours and I think I’ve worked out the way around it, hopefully this is of some use to you or anyone else that stumbles upon this thread:
I’ve been shooting on my iPhone 4S, (Quicktime plays them without sync slippage and displays the following settings: H264, 1920×1080, AAC, 44100 Hz)
So I transcoded the footage in MPEG Streamclip to Apple Pro Res 422 Proxy to edit (i often use proxy, smaller file size with very little loss of quality) and I didn’t pay much attention to the settings except to get the frame rate right. Weirdly some clips I’ve filmed are 29.97fps and some are 24, but that’s a confusing matter for another day.I brought the footage into FCP7, saying yes to the dialogue box to change the sequence settings to match the clips. But after some trouble shooting, I found that the sequence settings were not actually changing the audio from 48khz to 44.1 khz to match the footage, hence the slippage. So I changed it manually and re-imported my footage. I also found I had to re-transcode the footage (no idea why) and select 44.1khz instead of ‘Auto’ in the sound settings.
There’s definitely something buggy going on, but that worked for me.
Now to try and understand why some stuff i shot is at 29.97 and some is at 24fps…. Hmmm.
Sera
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