4.1

Chapter 4 Advanced adjustments 39
Retiming
This section contains one property:
•
Set duration to: Sets the processing algorithm used to adjust the frame rate during transcoding.
Select one of the following options:
•
[Percentage] of source: Modies the output clip’s speed by a percentage of the source clip’s
speed. Enter a value in the percentage eld or choose a preset value from the adjacent
pop-up menu (with a downward arrow).
•
[Total duration]: Sets the duration of the clip. Enter a timecode duration in the eld or click
the arrows to increase or decrease the time.
•
So source frames play at [frame rate] fps: Nondestructively changes the playback speed of the
clip, without discarding frames or creating new frames. This setting has no eect unless the
“Frame rate” value in the Video inspector is dierent than the source le’s frame rate. For
example, if you add a 10-second source le with a frame rate of 24 fps to Compressor, set the
“Frame rate” property in the Video inspector to 25 fps, and then select “So source frames play
at 25 fps” in the General inspector, the duration of the transcoded clip (at 25 fps) is 9 seconds
and 15 frames.
For more information, see Retime video and audio output on page 71.
Video properties
•
Frame size: Use the pop-up menu to set the frame size (resolution) for the output le.
•
Pixel aspect ratio: Use the pop-up menu to set the pixel aspect ratio (the ratio between the
image frame width and height). You can also modify the aspect ratio of the output le using
cropping and padding properties. For more information, see Modify frame size overview on
page 69.
•
Frame rate: Use this pop-up menu to set the playback rate (the number of images displayed
per second) for the output le. For more information, see Frame rate options overview on
page 71.
•
Field order: Use the pop-up menu to set the output scanning method (either the eld
dominance or a conversion to progressive scanning). There are four options:
•
Same as Source: Maintains the same scanning method used by the source media le.
•
Progressive: Scans complete frames (not frames divided into interlaced elds).
•
Top First: Scans interlaced elds, giving dominance (eld order) to the top eld, also known
as eld two, the upper eld, or the odd eld.
•
Bottom First: Scans interlaced elds, giving dominance (eld order) to the bottom eld, also
known as eld one, the lower eld, or the even eld.
•
Anamorphic: Set the aspect ratio using this pop-up menu. Choose Automatic to have
Compressor scale the image based on the frame size, or choose 16:9 or 4:3 to set anamorphic
scaling to a standard aspect ratio.
•
Encoding mode: Choose an option from the pop-up menu to set how Compressor encodes the
output le: either faster and lower quality, or slower and better quality. Options include:
•
Single Pass CBR: This is the fastest MPEG-2 encoding mode. It provides good quality,
especially at bit rates between 5 and 9 Mbps.
•
Single Pass VBR: This mode aims to maintain constant quality (at the expense of constant bit
rate) for the transcoded video le. For most standard-denition (SD) media les at bit rates
of 3.5 Mbps and above, this mode provides good to excellent quality and transcodes quickly.
•
Single Pass VBR (Best): This mode provides the best possible quality output for SD video at bit
rates of 3 to 3.5 Mbps and above.
67% resize factor