视频编解码常见名词解释

DPB

Decoded Picture Buffer; an H.264/HEVC term for a buffer that stores a decoded raw frame available for reference in further decoding steps.

EOS

end of stream.

IDR

Instantaneous Decoder Refresh; a type of a keyframe in an H.264/HEVC-encoded stream, which clears the list of earlier reference frames (DPBs).

keyframe

an encoded frame that does not reference frames decoded earlier, i.e. can be decoded fully on its own.

macroblock

a processing unit in image and video compression formats based on linear block transforms (e.g. H.264, VP8, VP9); codec-specific, but for most of popular codecs the size is 16x16 samples (pixels). The HEVC codec uses a slightly more flexible processing unit called coding tree unit (CTU).

resume point

a point in the bytestream from which decoding may start/continue, without any previous state/data present, e.g.: a keyframe (VP8/VP9) or SPS/PPS/IDR sequence (H.264/HEVC); a resume point is required to start decode of a new stream, or to resume decoding after a seek.

visible resolution

stream resolution of the visible picture, in pixels, to be used for display purposes; must be smaller or equal to coded resolution; display resolution.

coded resolution

stream resolution in pixels aligned to codec and hardware requirements; typically visible resolution rounded up to full macroblocks; see also: visible resolution.