Apparatus for dual pass rate control video encoding
AssigneeGoogle Technology Holdings LLC
InventorsMayer D. Schwartz, Peter A. Borgwardt, Shiv Saxena, Brenda L. Van Veldhuisen
Life of this patent
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Abstract
A dual-pass rate control video encoder including a first pass encoder module configured to receive uncompressed input video including a sequence of pictures, the input video including a plurality of contiguous sequences of pictures each referred to as a Group of Pictures (GOP) that, when coded, begin with an I-picture in display order and end with a last picture before a next I-picture, detect scene changes within the input video. The dual-pass rate control video encoder including a second pass encoder module configured to receive the uncompressed input video via a delay unit.
Claims22
A dual-pass rate control video encoder, comprising:
- a first pass encoder module including a memory and configured to:
- receive uncompressed input video including a sequence of pictures, the input video including a plurality of contiguous sequences of pictures each referred to as a Group of Pictures (GOP) that, when coded, begin with an I-picture in display order and end with a last picture before a next I-picture, detect scene changes within the input video,
- assign macroblocks to a pre-determined number of activity classes, and
- determine a complexity of each picture within the sequence of pictures,
- the macroblocks each being a rectangular array of luma samples and two corresponding blocks of chroma samples in the pictures, the activity class each being a defined class of macroblocks based on luma values of the pictures of the input video, and the complexity being a number of bits generated per picture and activity class;
- a storage and delay unit configured to receive the uncompressed input video;
- and
- a second pass encoder module including a memory and configured to:
- receive the uncompressed input video via the storage and delay unit,
- obtain information from the first pass encoder module concerning the scene changes, the activity classes, and the complexity used to produce the rate control of the uncompressed video, and
- produce a bit stream of compressed video,
- at least one of the first pass encoder module and the second pass encoder module configured to adjust boundaries of at least some of the GOPs to be aligned with the scene changes.
A dual-pass rate control video encoder, comprising:
- a first pass encoder module including a memory, and during a first encoding pass, configured to:
- receive uncompressed input video including a sequence of pictures with a video encoder, the input video including a plurality of contiguous sequences of pictures each referred to as a Group of Pictures (GOP) that, when coded, begin with an I-picture in display order and end with a last picture before a next I-picture;
- detect scene changes within the input video,
- assign macroblocks to a pre-determined number of activity classes, and
- determine a complexity of each picture within the sequence of pictures,
- the macroblocks being a rectangular array of luma samples and two corresponding blocks of chroma samples in the pictures, the activity classes being each being a defined class of macroblocks based on luma values of the pictures of the input video, and the complexity being a number of bits generated per picture and activity class;
- and
- a second pass encoder module including a memory, and during a second encoding pass, configured to obtain information from the first pass encoder module concerning the scene changes, the activity classes, and the complexity being used for rate control determined in the second encoding pass for producing and outputting a bit stream of compressed video,
- at least one of the first pass encoder module and the second pass encoder module configured to adjust boundaries of at least some of the GOPs to be aligned with the scene changes.
Dependencies are inferred from the claim text.