Commit 87c436fb authored by Yaowu Xu's avatar Yaowu Xu

Fix comments for encoder controls

This commit added coments for the following encoder controls:
VP9E_SET_LOSSLESS
VP9E_SET_TILE_COLUMNS
VP9E_SET_TILE_ROWS
VP9E_SET_FRAME_PARALLEL_DECODING
VP9E_SET_AQ_MODE

Change-Id: I2f75afd9cce01394f202b8e25f36bf763be0ddeb
parent 0337bae9
......@@ -234,11 +234,79 @@ enum vp8e_enc_control_id {
VP8E_SET_SCREEN_CONTENT_MODE, /**<control function to set encoder screen content mode */
/* TODO(jkoleszar): Move to vp9cx.h */
/*!\brief Codec control function to set lossless encoding mode
*
* VP9 can operate in lossless encoding mode, in which the bitstream
* produced will be able to decode and reconstruct a perfect copy of
* input source. This control function provides a mean to switch encoder
* into lossless coding mode(1) or normal coding mode(0) that may be lossy.
* 0 = lossy coding mode
* 1 = lossless coding mode
*
* By default, encoder operates in normal coding mode (maybe lossy).
*/
VP9E_SET_LOSSLESS,
/*!\brief Codec control function to set number of tile columns
*
* In encoding and decoding, VP9 allows an input image frame be partitioned
* into separated vertical tile columns, which can be encoded or decoded
* independently. This enables easy implementation of parallel encoding and
* decoding. This control requests the encoder to use column tiles in
* encoding an input frame, with number of tile columns (in Log2 unit) as
* the parameter:
* 0 = 1 tile column
* 1 = 2 tile columns
* 2 = 4 tile columns
* .....
* n = 2**n tile columns
* The requested tile columns will be capped by encoder based on image size
* limitation (The minimum width of a tile column is 256 pixel, the maximum
* is 4096).
*
* By default, the value is 0, i.e. one single column tile for entire image.
*/
VP9E_SET_TILE_COLUMNS,
/*!\brief Codec control function to set number of tile rows
*
* In encoding and decoding, VP9 allows an input image frame be partitioned
* into separated horizontal tile rows. Tile rows are encoded or decoded
* sequentially. Even though encoding/decoding of later tile rows depends on
* earlier ones, this allows the encoder to output data packets for tile rows
* prior to completely processing all tile rows in a frame, thereby reducing
* the latency in processing between input and output. The parameter
* for this control describes the number of tile rows, which has a valid
* range [0, 2]:
* 0 = 1 tile row
* 1 = 2 tile rows
* 2 = 4 tile rows
*
* By default, the value is 0, i.e. one single row tile for entire image.
*/
VP9E_SET_TILE_ROWS,
/*!\brief Codec control function to enable frame parallel decoding feature
*
* VP9 has a bitstream feature to reduce decoding dependency between frames
* by turning off backward update of probability context used in encoding
* and decoding. This allows staged parallel processing of more than one
* video frames in the decoder. This control function provides a mean to
* turn this feature on or off for bitstreams produced by encoder.
*
* By default, this feature is off.
*/
VP9E_SET_FRAME_PARALLEL_DECODING,
/*!\brief Codec control function to set adaptive quantization mode
*
* VP9 has a segment based feature that allows encoder to adaptively change
* quantization parameter for each segment within a frame to improve the
* subjective quality. This control makes encoder operate in one of the
* several AQ_modes supported.
*
* By default, encoder operates with AQ_Mode 0(adaptive quantization off).
*/
VP9E_SET_AQ_MODE,
VP9E_SET_FRAME_PERIODIC_BOOST,
/*!\brief control function to set noise sensitivity
......
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