Abstract: Techniques are described for efficiently encoding video data by skipping evaluation of certain encoding modes based on various evaluation criteria. In some solutions, intra-block evaluation is performed in a specific order during encoding, and depending on encoding cost calculations of potential intra-block encoding modes, evaluation of some of the potential modes can be skipped. In some solutions, some encoding modes can be skipped depending on whether blocks are simple (e.g., simple vertical, simple horizontal, or both) or non-simple. In some solutions, various criteria are applied to determine whether chroma-from-luma mode evaluation can be skipped. The various solutions can be used independently and/or in combination.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: A video codec uses fractional increments of quantization step size at high bit rates to permit a more continuous variation of quality and/or bit rate as the quantization scale changes. For high bit rate scenarios, the bit stream syntax includes an additional syntax element to specify fractional step increments (e.g., half step) of the normal quantizer scale step sizes.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: Techniques are described for efficiently encoding video data by skipping evaluation of certain encoding modes based on various evaluation criteria. In some solutions, intra-block evaluation is performed in a specific order during encoding, and depending on encoding cost calculations of potential intra-block encoding modes, evaluation of some of the potential modes can be skipped. In some solutions, some encoding modes can be skipped depending on whether blocks are simple (e.g., simple vertical, simple horizontal, or both) or non-simple. In some solutions, various criteria are applied to determine whether chroma-from-luma mode evaluation can be skipped. The various solutions can be used independently and/or in combination.

Abstract: With adaptive multiple quantization, a video or other digital media codec can adaptively select among multiple quantizers to apply to transform coefficients. The switch in quantizers can be signaled at the sequence level or frame level of the bitstream syntax, or can be implicitly specified in the syntax.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: A video codec uses fractional increments of quantization step size at high bit rates to permit a more continuous variation of quality and/or bit rate as the quantization scale changes. For high bit rate scenarios, the bit stream syntax includes an additional syntax element to specify fractional step increments (e.g., half step) of the normal quantizer scale step sizes.

Abstract: With adaptive multiple quantization, a video or other digital media codec can adaptively select among multiple quantizers to apply to transform coefficients. The switch in quantizers can be signaled at the sequence level or frame level of the bitstream syntax, or can be implicitly specified in the syntax.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: A video codec uses fractional increments of quantization step size at high bit rates to permit a more continuous variation of quality and/or bit rate as the quantization scale changes. For high bit rate scenarios, the bit stream syntax includes an additional syntax element to specify fractional step increments (e.g., half step) of the normal quantizer scale step sizes.

Abstract: Techniques are described for efficiently encoding video data by skipping evaluation of certain encoding modes based on various evaluation criteria. In some solutions, intra-block evaluation is performed in a specific order during encoding, and depending on encoding cost calculations of potential intra-block encoding modes, evaluation of some of the potential modes can be skipped. In some solutions, some encoding modes can be skipped depending on whether blocks are simple (e.g., simple vertical, simple horizontal, or both) or non-simple. In some solutions, various criteria are applied to determine whether chroma-from-luma mode evaluation can be skipped. The various solutions can be used independently and/or in combination.

Abstract: With adaptive multiple quantization, a video or other digital media codec can adaptively select among multiple quantizers to apply to transform coefficients. The switch in quantizers can be signaled at the sequence level or frame level of the bitstream syntax, or can be implicitly specified in the syntax.

Abstract: Innovations in hash table construction and hash-based block matching for image encoding or video encoding are described. For example, an encoder determines hash values for base-size candidate blocks in a reference picture. The encoder stores, in a hash table, the hash values for the base-size candidate blocks. The encoder encodes a trial-size current block in a current picture. In some cases, the trial-size current block has a block size larger than the base block size. As part of the encoding, the encoder uses hash-based block matching, between base-size current blocks of the trial-size current block and the base-size candidate blocks, to identify a trial-size matching block, if any, in the reference picture. The encoder stores hash values only for the base-size candidate blocks. This can significantly reduce the computational cost and memory cost for hash table construction during encoding, without hurting compression efficiency or the overall speed of encoding.

Abstract: Innovations in hash table construction and hash-based block matching for image encoding or video encoding are described. For example, an encoder determines hash values for base-size candidate blocks in a reference picture. The encoder stores, in a hash table, the hash values for the base-size candidate blocks. The encoder encodes a trial-size current block in a current picture. In some cases, the trial-size current block has a block size larger than the base block size. As part of the encoding, the encoder uses hash-based block matching, between base-size current blocks of the trial-size current block and the base-size candidate blocks, to identify a trial-size matching block, if any, in the reference picture. The encoder stores hash values only for the base-size candidate blocks. This can significantly reduce the computational cost and memory cost for hash table construction during encoding, without hurting compression efficiency or the overall speed of encoding.

Abstract: Techniques are described for efficiently encoding video data by skipping evaluation of certain encoding modes based on various evaluation criteria. In some solutions, intra-block evaluation is performed in a specific order during encoding, and depending on encoding cost calculations of potential intra-block encoding modes, evaluation of some of the potential modes can be skipped. In some solutions, some encoding modes can be skipped depending on whether blocks are simple (e.g., simple vertical, simple horizontal, or both) or non-simple. In some solutions, various criteria are applied to determine whether chroma-from-luma mode evaluation can be skipped. The various solutions can be used independently and/or in combination.

Abstract: Techniques are described for efficiently encoding video data by skipping evaluation of certain encoding modes based on various evaluation criteria. In some solutions, intra-block evaluation is performed in a specific order during encoding, and depending on encoding cost calculations of potential intra-block encoding modes, evaluation of some of the potential modes can be skipped. In some solutions, some encoding modes can be skipped depending on whether blocks are simple (e.g., simple vertical, simple horizontal, or both) or non-simple. In some solutions, various criteria are applied to determine whether chroma-from-luma mode evaluation can be skipped. The various solutions can be used independently and/or in combination.

Abstract: Techniques and tools are described for decoding jointly coded information. For example, a decoder decodes a variable length code [“VLC”] signaled at macroblock level that jointly represents a transform type signal level, transform type, and subblock pattern. The decoder decodes one or more VLCs signaled at block level, each jointly representing a transform type and subblock pattern. The decoder may select between multiple VLC tables for the VLCs signaled macroblock level and/or block level.

Abstract: A video codec uses fractional increments of quantization step size at high bit rates to permit a more continuous variation of quality and/or bit rate as the quantization scale changes. For high bit rate scenarios, the bit stream syntax includes an additional syntax element to specify fractional step increments (e.g., half step) of the normal quantizer scale step sizes.