Media Composer Frame Rate Conversion

video-conversions.jpg

I came across a posting on the Avid Editors of Facebook where someone was extolling the quality of Apple Compressor’s frame rate conversion. Others just advised to use Media Composer to convert. Personally I have not really used Compressor on a regular basis, so I thought I would put it to the test and compare it to Media Composer. For this test, I went with the following scenario; standard definition interlace material in a 1080p/23.976. This is pretty common with clip shows that go back into their digital archive.

I found a source clip that had both camera motion (zoom) and content motion (truck driving by) that originated on an SD 29.97 interlace format. The timeline is 1080p/23.976 and represents three (not counting color space) conversions:

  • Interlace to progressive
  • Frame rate conversion
  • Motion

In Compressor, I selected “Best quality” for both “Resize Filter” and “Retiming Quality”.

In Media Composer, I used several methods and motion algorithms in order to find the best quality conversion.

  • Source Clip Transcode from AMA link to original file
  • Edited the AMA linked original file and made 7 sequences and applied a different motion effect type as seen in the Motion Effect Editor”

motion-effects.jpg

Whenever possible, I used the motion “Adaptive Deinterlace Source” setting as seen here as in all cases it was a better quality conversion when dealing with this type footage and conversion:

adaptive-deinterlace.png

Keep in mind when judging image quality via the GUI viewers in Media Composer that do not show the full frame, and if you are, make sure you are in green/green mode and not in any proxy modes. You are better off judging quality on the client monitor in green/green mode or exporting a series of frames and look at those.

In all cases the Apple Compressor conversion delivered a better quality image. There are a few Media Composer Motion Effect settings that can be used to get close as seen in the example frames below.

It is unfortunate that source clip transcode to project rate is actually one of the poorer quality versions as it defaults to “Blended Interpolated”and there is no way to change that for source transcodes. Setting a preferred render type in Render settings does not affect the type of transcode being used.

So now the user has to manage the quality on the timeline and can set the default render to their preferred look before rendering the effects. The downside is this is not ideal when making new source masters you might want to archive from the project itself. in most cases, the uprez also looked a bit better with Compressor, but that may be a side effect of the field interpolation. Another test will need to be done on matching formats to judge uprez only. In this particular test, FluidMotion did a good job and came closest to matching Compressor on motion but that can be hit and miss depending on footage without going in and editing vectors.

For all Frames, click to see full resolution.

Apple Compressor:

truck_compressor.jpg

 

Source Clip Transcode:

truck_source-transcode.jpg

Motion Effect: Blended Interpolated:

truck_blended-interpolated.jpg

Motion Effect: Blended-VTR:

truck_blended-vtr.jpg

Motion Effect: Interpolated Field:

truck_interpolated-field.jpg

Motion Effect: VTR Style:

truck_vtr-style.jpg

Motion Effect: Both Fields:

both-fields.jpg

Motion Effect: FluidMotion:

truck_fluidmotion.jpg

One thing I noticed is the timecode conversion from 29.97DF to 24 was different than what Media Composer does with its timecode conversion. Media Composer converts at the start of the second in this type of conversion, I haven’t yet figured out what Compressor is using as a calculation:

Original File timecode:            01;02;33;25
Compressor Conversion:         01:02:31:21
Media Composer Conversion: 01:02:33:20

The timecode is something to keep in mind when doing conversions if ever needing to go back to camera/file master. If you are using Compressor, I would recommend a transcode to a new submaster and choose a finishing quality to start.

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