Complexity Reduction For VP6 To H.264 Transcoder Using Motion Vector Reuse

VP6 is a video coding standard developed by On2 Technologies, Inc. It is the preferred codec for Macromedia Flash 8 video. VP6 gained importance with Macromedia Flash emerging as a widely adopted video streaming technology over the internet. H.264 is currently one of the most widely accepted video coding standards in the industry. It enables high quality video at low bitrates. Adobe adopted H.264 for its Flash video in August 2007. Adobe looks at adoption of H.264 as a major step towards enabling high quality video on the web. Hence there is increasing importance of techniques which can convert video from VP6 to H.264 and thereby enable high quality video transmission over the internet using Flash. VP6 and H.264 are modern standards bearing a lot of similarities and dissimilarities. While H.264 is a complex coding standard with sophisticated coding tools to reduce the bitrate as much as possible without compromising on the quality, VP6 is much simpler and less strenuous on the processor. The VP6 standard is not able to meet the quality levels of H.264 at given bitrates; but the perceived image quality is still very good. VP6 also makes use of up to quarter-pixel accuracy motion vectors like H.264 albeit with fewer block sizes for motion estimation. Making re-use of these motion vectors available from the decoded VP6 file can reduce the underlying encoding complexity in the transcoder to a very large extent. Also the corresponding compromise on quality is very less. The proposed technique as shown in this research can bring down the complexity significantly without much compromise in the transcoded video quality.