• Compression Techniques

  MOV H.262 halving frame rate on compression

  Posted by Dimos Chatzipanteliadis on August 18, 2009 at 3:54 pm

  Hi guys,

  I exported a MOV file through Apple Compressor: @ 25fps, H264, 1920×1080, 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, 1280×720, 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

  Daniel Low replied 17 years ago 2 Members · 2 Replies
• 2 Replies

• 

  Dimos Chatzipanteliadis

  August 18, 2009 at 5:20 pm

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

  Name: Untitled
  Description: QuickTime H.264 1280×720 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
• 

  Daniel Low

  August 18, 2009 at 9:02 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 https://www.yousendit.com so we can have a look at it.

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