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MOV H.262 halving frame rate on compression

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Dimos Chatzipanteliadis
MOV H.262 halving frame rate on compression
on Aug 18, 2009 at 3:54:28 pm

Hi guys,

I exported a MOV file through Apple Compressor: @ 25fps, H264, 1920x1080, 35 Mbit/s and PCM Stereo sound. I needed however to get a smaller version of the clip so I used compressor with the above file as a source. The output that I wanted was to be @25 fps, 1280x720, AAC audio (not quite sure about required bit rate).

After submitting the above in Compressor and choosing the option "frame rate same as source" I get a MOV file which complies with the above requirements however the 25fps are actually half, as every frame is repeated. This results in a jaggy futage as if it was 12fps and not 25fps (which its is)

I tried various settings in Compressor but seem always to get (effectively) half the input's frame rate! There is nothing I can see in Compressor that would indicate this will happen.

Why is this? How can I get a real 25fps compressed clip?

Cheers
Dimos


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Dimos Chatzipanteliadis
Re: MOV H.262 halving frame rate on compression
on Aug 18, 2009 at 5:20:24 pm

Following are the settings I use for the reduced size clip that I want to produce.

Name: Untitled
Description: QuickTime H.264 1280x720 video with AAC audio at 41 kHz. Settings based off the source resolution and frame-rate.
File Extension: mov
Estimated file size: unknown
Time remapping:output duration 100.021492%
Audio Encoder
AAC, Stereo (L R), 44.100 kHz

Video Encoder
Format: QT
Width: 1280
Height: 720
Pixel aspect ratio: Square
Crop: None
Padding: None
Frame rate: 25
Frame Controls On:

Retiming: (Fast) Nearest Frame
Resize Filter: Linear Filter
Deinterlace Filter: Fast (Line Averaging)
Adaptive Details: On
Antialias: 0
Detail Level: 0
Field Output: Same as Source

Codec Type: H.264
Multi-pass: Off, frame reorder: On
Pixel depth: 24
Spatial quality: 75
Min. Spatial quality: 25
Temporal quality: 50
Min. temporal quality: 25


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Daniel Low
Re: MOV H.262 halving frame rate on compression
on Aug 18, 2009 at 9:02:22 pm

Try turning off the 'Retiming' and set the output explicity to 25fps. Is your source progressive? If so turn of deinterlacing

If that fails post the Compressor project and preset to http://www.yousendit.com so we can have a look at it.

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