ref: 87c436fbe2562ef3dec3a0720690b52c3291fa61
parent: 0337bae9b3cdb2869073911b0efc2b4f3cfcf595
author: Yaowu Xu <yaowu@google.com>
date: Tue Jan 13 07:39:42 EST 2015
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
--- a/vpx/vp8cx.h
+++ b/vpx/vp8cx.h
@@ -234,11 +234,79 @@
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