Change the Encoding of a Movie Clip

Problem

You want to change the encoding of a movie clip.

Solution

Use the VideoDecoder to decode your existing clip and then use the VideoEncoder to encode that clip into a different codec. For example, the following code converts an input QuickTime to h.264.

image = Draft.Image.CreateImage( 1, 1 )

decoder = Draft.VideoDecoder( "//path/to/existing/clip.mov" )

hasFrames = decoder.DecodeNextFrame( image )
if hasFrames:
    encoder = Draft.VideoEncoder( "//path/to/video/save.mov", codec='H264' )

    while hasFrames:
        encoder.EncodeNextFrame( image )
        hasFrames = decoder.DecodeNextFrame( image )

    encoder.FinalizeEncoding()

Discussion

Taking a movie clip and encoding it with a new codec is just a matter of decoding the existing clip and encoding it into a new clip. An important thing to remember is that the paths for the decoder and the encoder must be different. You can’t decode and encode the same file at the same time.

Draft will detect which decoder to use automatically so you do not need to specify when you are decoding.

Draft supports multiple codec options. They include:

• MPEG4 (default)
• MJPEG
• DNxHD® (requires a “Draft Codec Pack” license)
• H264
• RAWVIDEO

It’s important to remember that when you’re encoding with Avid DNxHD® you must use a specific set of parameters. Here is a table of all the Avid DNxHD® settings that work with this version of Draft.

width	height	fps	kbitRate
1920	1080	29.97	220000
1920	1080	29.97	145000
1920	1080	29.97	45000
1920	1080	25	185000 *
1920	1080	25	120000 *
1920	1080	25	36000 *
1920	1080	24	175000 *
1920	1080	24	115000 *
1920	1080	24	36000 *
1920	1080	23.976	175000
1920	1080	23.976	115000
1920	1080	23.976	36000
1280	720	59.94	220000
1280	720	59.94	145000
1280	720	50	180000
1280	720	50	120000
1280	720	29.97	110000
1280	720	29.97	75000
1280	720	25	90000
1280	720	25	60000
1280	720	23.976	90000
1280	720	23.976	60000

* Draft supports writing MXF files for these combinations only