SVC-to-AVC rewriter with open-loop statistical multiplexer
View Patent ↗A method is provided for processing multilayer bit streams that includes receiving the multilayer bit streams of Scalable Video Code (SVC) each having a base layer and at least one enhancement layer. One or more of the enhancement layers are extracted in whole or in part from at least one of the multilayer bit streams so that the multilayer bit streams are collectively reduced in their total bandwidth. Each of the extracted bit streams are rewritten to a single layer bit stream. The single layer bit streams are then multiplexed to form a multiplexed single layer bit stream that is non-SVC.
1. An apparatus for statistically multiplexing and rewriting a scalable bit stream, comprising:
a plurality of bit rate extraction units for receiving a plurality of multilayer scalable video code (SVC) bit streams, said bit rate extraction units each being configured to extract one or more enhancement layers in whole or in part from at least one of the multilayer bit streams,
a bit rate allocation manager,
wherein the bit rate allocation manager obtains bit rate allocation management parameters from a video service provider,
wherein a bit rate allocation manager determines a bit rate to allocate to each of the multilayer bit streams based at least in part on the bit rate allocation management parameters, and information pertaining to a channel over which a multiplexed single layer non-SVC bit stream is to be transported;
a storage database wherein the bit rate allocation management parameters are stored and are accessible to the bit rate allocation manager;
wherein the bit rate allocation manager produces the bit rate allocations for simultaneous programs in a manner that tends to equalize video across programs to the extent that is consistent with the bit rate allocation management parameters specified by the video service provider;
a plurality of multilayer to single-layer rewriters for converting the plurality of multilayer bit streams received from the bit rate extraction units to a plurality of single-layer bit streams,
wherein the rewriter selects ones of the enhancement layers for each program in a manner that is consistent with the bit rate allocation determined by the bit rate allocation manager,
wherein the rewriter extracts one or more of the enhancement layers in whole or in part from at least one of the multilayer bit streams so that so that the plurality of multilayer bit streams are collectively reduced in their total bandwidth, and so that each program in each of the enhancement layers is provided in such a manner that is consistent with the bit rate allocation and the bit rate allocation parameters;
wherein the rewriter rewrites each of the extracted enhancement layers to produce a single layer bit stream for each of the extracted enhancement layers; and
a multiplexer for multiplexing the single layer bit streams to form the non-SVC multiplexed single layer bit stream.
2. The apparatus of claim 1 further comprising:
a channel model database for storing information pertaining to capacities and requirements of channels over which the bit streams can be transmitted; and
a bit rate allocation manager for determining the one or more enhancement layers that are to be extracted by the bit rate extraction units based at least in part on the information in the channel model database.
3. The apparatus of claim 2 wherein the bit rate allocation manager allocates bit rates to each of the multilayer bit streams based at least in part on a priority assigned to each of the streams such that multilayer bit streams having a common priority are each allocated a bit rate needed to produce a common level of perceptual quality.
4. The apparatus of claim 1 wherein the bit rate extraction units are configured to distinguish between packet ID types assigned to packets that carry base layer information and packet ID types assigned to packets that carry enhancement layer information.
5. The apparatus of claim 1 wherein the multilayer bit streams conform to a scalable video coding (SVC) standard and the single layer bit streams conform to an advanced video coding (AVC) standard, and wherein the plurality of bit rate extraction units receive the SVC bit streams prior to the multiplexer multiplexing the single layer bit streams to form a non-SVC multiplexed single layer bit stream.
6. The apparatus of claim 1 , wherein in the bit rate allocation management parameters used by the bit rate allocation manager include at least one of program stream priority, maximum program resolution, maximum program bit rate and maximum total bit rate that may be allocated.
7. The apparatus of claim 1 , wherein rewriter selects enhancement layers for each program particularly based on resolution and frame rate.
8. The apparatus of claim 1 wherein bit rate adaptation is performed in accordance with an open-loop technique.