C200: XF-AVC vs MP4?

brettsherman

brettsherman

Well-known member
I haven’t upgraded my firmware yet. For those who have started shooting on XF-AVC is there any quality difference with MP4? Are there any other advantages?
 
I know the Metadata does work so well since the MP4 does not give you anything. As far as the contrast? or colors? anyone really did see a change?

any thoughts on this?
 
One note. If you import XF-AVC footage shot at 120fps in FCPX, you'll crash. MP4 slow motion footage imports without any problems.
 
For some reason event XF-AVC footage in AP is slow and jumpy even in 1/4 or 1/8 playback - May needs a stronger machine than a MacBook Pro 2017. (any similar situations?)
 
rocstudios said:
For some reason event XF-AVC footage in AP is slow and jumpy even in 1/4 or 1/8 playback - May needs a stronger machine than a MacBook Pro 2017. (any similar situations?)
Click to expand...

Tested on a late 2013 MBP GTX 750M, Premiere Pro (latest) using C300 II XF-AVC footage:

1. a.mxf original 422 10-bit 4K: near 100% CPU playback (no adjustments, smooth)
2. ffmpeg -i a.mxf -c:v copy a.mp4. Here we copied the video stream unchanged, and converted the uncompressed audio to compressed AAC. Same results as (1): near 100% CPU. Checking to see if MXF has a different decoder path vs. MP4.
3. ffmpeg -i a.mxf a2.mp4. Here we transcoded from 422 10-bit intra (ALL-I) to 422 8-bit inter (IPB) (1.1GB file => 32MB file) and AAC audio. Near zero CPU usage.

This indicates that case (3) uses the GPU, and (1) & (2) are at least substantially using the CPU. This could be the case with the C200: XF-AVC uses the CPU, MP4 uses the GPU. Could also explain crash issue with FCPX.

If the video stream is the same for XF-AVC and MP4, then the only difference is uncompressed vs. compressed audio.
 
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