摘要:
A source device may signal characteristics of a media presentation description (MPD) file such that a destination device may select one of a number of presentations corresponding to the MPD file and retrieve one or more video files of the selected presentation. In one example, an apparatus for transporting encoded video data includes a management unit configured to receive encoded video data comprising a number of video segments and forms a presentation comprising a number of video files, each of the video files corresponding to a respective one of the video segments, and a network interface configured to, in response to a request specifying a temporal section of the video data, output at least one of the video files corresponding to the number of video segments of the requested temporal section. A client may request temporally sequential fragments from different ones of the presentations.
摘要:
A method and a device are described for selecting between multiple available filters in an encoder to provide a frame having a low error and distortion rate. For each full and sub pixel position, determining whether to use an alternative filter over the default filter during interpolation by estimating the rate distortion gain of using each filter and signaling to the decoder the optimal filter(s) applied to each full and sub-pixel position. In one embodiment, identifying a reference frame and a current frame, interpolating the reference frame using a default filter to create a default interpolated frame, interpolating the reference frame using an alternative filter to create an alternative interpolated frame, determining for each sub-pixel position whether to use the default filter or the alternative filter based on a minimal cost to generate a final reference frame.
摘要:
A demultiplexer may assemble view components of sub-bitstreams. In one example, an apparatus comprises a demultiplexer that produces a multiview video coding (MVC) standard compliant bitstream from a received bitstream comprising a primary sub-bitstream and an embedded sub-bitstream. To produce the MVC standard compliant bitstream, the demultiplexer determines whether a view component of the primary sub-bitstream has a view order index that is greater than a view order index of a view component of the embedded sub-bitstream, and to add the view component from the sub-bitstream for which the view order index is lower to the produced bitstream. The received bitstream may comprise delimiter network abstraction layer (NAL) units between each view component to differentiate the view components. The apparatus may further comprise a video decoder to decode the bitstream produced by the demultiplexer.
摘要:
In one aspect of this disclosure, techniques are described for selecting among default weighted prediction, implicit weighted prediction, and explicit weighted prediction. In this context, techniques are also described for adding offset to prediction data, e.g., using the format of explicit weighted prediction to allow for offsets to predictive data that is otherwise determined by implicit or default weighted prediction.
摘要:
This disclosure describes video encoding and decoding techniques in which a first order prediction process and a second order prediction process are used in combination to generate predictive video blocks for video coding. First order prediction may be similar to conventional motion estimation and motion compensation that generates residual video blocks. The second order prediction may involve a process similar to conventional intra-prediction, but is performed on the residual video blocks. The techniques of this disclosure may pre-define the second order prediction to a specific mode, such as a mode similar to the intra-DC mode used in intra coding. In addition, the techniques of this disclosure may combine aspects of the first order and second order prediction into a single process so that the effects of second order prediction on the residuals are taken into account during the first order prediction process, which may improve compression.
摘要:
Techniques are described for encoding and decoding digital video data using macroblocks that are larger than the macroblocks prescribed by conventional video encoding and decoding standards. For example, the techniques include encoding and decoding a video stream using macroblocks comprising greater than 16×16 pixels, for example, 64×64 pixels. In one example, an apparatus includes a video encoder configured to encode a video block having a size of more than 16×16 pixels, generate block-type syntax information that indicates the size of the block, and generate a coded block pattern value for the encoded block, wherein the coded block pattern value indicates whether the encoded block includes at least one non-zero coefficient. The encoder may set the coded block pattern value to zero when the encoded block does not include at least one non-zero coefficient or set the coded block pattern value to one when the encoded block includes a non-zero coefficient.
摘要:
This disclosure describes techniques for transforming residual blocks of video data. In particular, a plurality of different transforms selectively applied to the residual blocks based on the prediction mode of the video blocks. At least a portion of the plurality of transforms are separable directional transform specifically trained for a corresponding prediction mode to provide better energy compaction for the residual blocks of the given prediction mode. Using separable directional transforms offers the benefits of lower computation complexity and storage requirement than use of non-separable directional transforms. Additionally, a scan order used to scan the coefficients of the residual block may be adjusted when applying separable directional transforms. In particular, the scan order may be adjusted based on statistics associated with one or more previously coded blocks to better ensure that non-zero coefficients are grouped near the front of the one-dimensional coefficient vector to improve the effectiveness of entropy coding.
摘要:
This disclosure describes techniques for scanning coefficients of video blocks, e.g., quantized and transformed coefficients. Rather than use conventional zig-zag scanning, the techniques of this disclosure adapt the scanning order based on statistics associated with previously coded blocks that were coded in the same prediction mode. For each prediction mode, statistics of the coefficients are stored, e.g., indicating probabilities that given coefficients are zero or non-zero. Periodically, adjustments to the scanning order can be made in order to better ensure that non-zero coefficients are grouped together and zero value coefficients are grouped together, which can improve the effectiveness of entropy coding. The techniques of this disclosure provide thresholds and threshold adjustments that can reduce the frequency that the scanning order adjustments occur, yet still achieve desired improvements in compression due to such scanning order adjustments.
摘要:
This disclosure describes techniques for coding an enhancement layer in a scalable video coding (SVC) scheme. The techniques may be used in variable length coding of refinement coefficients of an enhancement layer of a SVC scheme. According to this disclosure, a method may comprise determining first statistics associated with a first type of video block. determining second statistics associated with a second type of video block, selecting a first variable length coding (VLC) table from a plurality of VLC tables to be used in coding the first type of video block based on the first statistics, selecting a second VLC table from the plurality of VLC tables to be used in coding the second type of video block based on the second statistics, coding video blocks of the first type based on the first VLC table, and coding video blocks of the second type based on the second VLC table.
摘要:
This disclosure describes techniques for coding information in a scalable video coding (SVC) scheme that supports spatial scalability. In one example, a method of coding information in a SVC scheme comprises coding first video blocks defined in a base layer of the SVC scheme, and coding second video blocks defined in an enhancement layer of the SVC scheme, wherein the second video blocks provide spatial scalability enhancement relative to the first video blocks. The coding of the second video blocks includes performing inter-layer prediction for the enhancement layer relative to the base layer for a first subset of the second video blocks that fully overlap the first video blocks, and performing inter-layer prediction for the enhancement layer relative to the base layer for a second subset of the second video blocks that partially overlap the first video blocks.