US20150271504A1

US20150271504A1 - Adaptable video architectures

Info

Publication number: US20150271504A1
Application number: US14/731,327
Authority: US
Inventors: Eben Upton; Graham Veitch; Alan Morgan; James Bennett
Original assignee: Broadcom Corp
Current assignee: Avago Technologies International Sales Pte Ltd
Priority date: 2011-07-20
Filing date: 2015-06-04
Publication date: 2015-09-24
Also published as: US9083951B2; US20130024652A1; US20130022101A1; US8832412B2

Abstract

Various methods and systems are provided for adaptable video architectures. In one embodiment, a method for adapting video processing of a video device includes processing a video stream along a first pipeline pathway defined by a plurality of interconnected pipeline elements. In response to detecting a change in a system condition of the video device, the pipeline pathway is transitioned to a second pipeline pathway by reconfiguring at least one of the pipeline element interconnections. In another embodiment, a method includes obtaining a video stream. A first subset bitstream having a first resolution is processed in a video pipeline of a video device and video information is extracted from the video pipeline during the processing. At least a portion of the extracted video information is then to a video pipeline of the video device for processing a second subset bitstream having a second resolution higher than the first resolution.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to copending U.S. provisional application entitled “MULTIMEDIA PROCESSING” having Ser. No. 61/509,797, filed Jul. 20, 2011, the entirety of which is hereby incorporated by reference.

BACKGROUND

Processing requirements are advancing as the world turns toward multimedia. The availability of internet multimedia content continues to improve with some sites supporting full high definition video sharing. The added use of video conferencing has also increased the demand for better quality and faster processing. In addition, cell phones are increasingly used as digital cameras and camcorders. The move to mobile equipment is increasing the demand for high resolution image processing with low power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a graphical representation of an example of a video device in accordance with various embodiments of the present disclosure.

FIG. 2 is a flow chart illustrating an example of the real time adaptation of video processing in accordance with various embodiments of the present disclosure.

FIG. 3 is a flow chart illustrating an example of scalable video pipeline processing in accordance with various embodiments of the present disclosure.

FIG. 4 is a flow chart illustrating an example of pixel block size decomposition of video pixel blocks in accordance with various embodiments of the present disclosure.

DETAILED DESCRIPTION

Image and multimedia processing may be provided through processing circuits implemented in individual chips or chip sets. For example, the multimedia processing may be implemented with a single chip having flexible and low power architecture. The processor architecture may be configured in hardware and/or software executed by processing hardware (e.g., a processing unit). Most conventional video coding architectures and designs are dedicated (hardware and/or software) to only one video coding standard and for servicing one video stream based thereon at a time.
The adaptable video architecture is implemented in both hardware and software executed by hardware. An adaptable video (transcode-encode-decode) architecture is configured to fully and simultaneously support any number of video stream types, where each type is defined by one of a plurality of video coding standards. The hardware is time-shared between the multiple streams to provide nearly simultaneous processing of the streams. The net effect of the fine-grained time-sharing is that it appears to a user that the multiple streams are handled simultaneously by the video architecture.
Most conventional video coding architectures are dedicated to a single video coding standard and for servicing one video stream at a time based upon that video coding standard. Software based architectures may be utilized for multiple standards but service only one stream at a time. In addition, the software based architectures face substantial limitations (especially for cutting edge standards) by not having access to dedicated hardware and for usurping general purpose processing resources. On the other hand, dedicated hardware places different power, space and cost demands on a design. To support multiple video coding standards in the architecture, compromises are made to implement each of the video coding standards: (a) in software (without hardware acceleration); (b) in dedicated hardware; or (c) at an inferior performance level (e.g., at a reduced frame rate, resolution, quality, etc.) via a combination of (a) and (b); or not implement (or support) a video coding standard at all. Further, once such compromises have been made, they become fixed design constraints that may or may not provide adequate service or underutilize the resources in a device under particular streaming circumstances. For example, MPEG2 may not have been implemented with hardware acceleration. However, a user's device may be used 99% of the time viewing MPEG2 streams, all the while dedicated H.264 hardware sits idle.
The adaptable transcode-encode-decode architecture uses two levels of architectural adaptability to overcome limitations. First, real time adaptation may be used to best support one or more simultaneous video streams. The streams may be of the same or differing video stream types. Second, a flexible architectural offering allows for design decision tailoring to fit a specific platform. For each coding standard (or type), several tiers of support (or stream pathways) may be offered to support multiple simultaneous video streams having the same or differing types. Such tiers involve transcode-encode-decode functional elements that may be carried out in software and/or with hardware acceleration. Serial, cyclic serial, parallel and combinations thereof may all be offered. This overall architectural offering with all underlying tiers may be fully integrated into a device or may be tailored to fit current design constraints by eliminating specific “element” tiers without requiring an underlying redesign.
Referring to FIG. 1, shown is a graphical representation of a video device 100 including, e.g., a transcoder, encoder, or decoder that includes one or more hardware pipelines 103 or tiers for processing one or more streams of video data. Each pipeline 103 includes a plurality of elements 106 for processing the video stream data. The pipelines 103 are configured to allow the interconnections 109 between the pipeline elements 106 to be diverted based upon system conditions of the video device and/or video stream. The pipeline pathway may be reconfigured by diverting at least one of the interconnections allow processing by other pipeline elements 106 and/or by software modules 112 executed by shared general-purpose processing resources of the video device.
All element tiers that make it into a device may function in a real time adaptive way to support shared processing resources for load balancing, multiple video stream conditions that arise during device use, and battery constraints. A pathway adaptation module executed by shared general-purpose processing resources of the video device monitors the conditions of the video device and controls rerouting the pipeline interconnections. Referring to FIG. 2, shown is a flow chart illustrating an example of the real time adaptation of a pipeline pathway 200. Beginning with box 203, a pipeline pathway 200 is defined for a first video stream. For example, in a decoder, a decode pathway 200 may be defined wherein each pipeline element 106 is selected for the highest performance but with substantial power utilization to service a single video stream. The decode pathway 200 may be implemented in hardware or a combination of hardware and software executed by shared general-purpose processing resources such as, e.g., a processor, application specific chip, and/or other appropriate hardware. In box 206, a change in one or more of the system conditions is detected. For example, during the visual presentation of a first video stream, battery conditions may change.
An alternate pathway may be selected in box 209 based at least in part upon the condition changes. For example, an alternative decoder pathway 200 a may be selected which offers better battery performance while delivering acceptable video quality. The alternate pipeline pathway 200 a may include, e.g., diverting the interconnections 109 between the pipeline elements 106 for processing by other pipeline elements 106 or by executed software modules 112, bypassing pipeline elements 106 (which may be deactivated to reduce power usage), and/or rerouting to another pipeline pathway. Alternate pipeline pathways 200 a may be selected from a plurality of predefined pipeline pathways based upon a defined set of conditions or may be determined using an expert system (or other appropriate pattern recognition system) based upon the system conditions. If an alternate pathway 200 a is selected, then the video stream transitions to the alternate pathway in box 212 (e.g., transition between the two pathways 200 and 200 a by synchronizing to a reference frame) and returns to box 206 to detect the next condition change. If an alternate pathway is not selected, then the video stream remains on the current pathway and returns to box 206 to detect the next condition change.
Another change in conditions may then be detected such as, e.g., a user selecting a second video stream of the same or different type to be displayed in a shared screen arrangement. Again, it is determined in box 209 if an alternate pathway should be used. For example, the decode architecture may adapt to best support the two streams by selecting various element tiers to form two pipeline pathways, one for processing each of the two streams. In box 212, the video streams are transitioned and the sequence returns to box 206 to detect the next condition change. The sequence continues adapting to additional changes in the conditions. For example, a non-video stream task operating on the device may place a higher demand on shared general-purpose processing resources, which is detected in box 206. In box 209, the decode architecture may adapt to minimize its reliance on such shared resources by selecting other decoder pipeline elements 106 that are either less shared-resource consumptive or operate in dedicated hardware. In box 212, the streams are transitioned before returning to box 206. These and other adaptation examples can apply equally to transcoder and encoder elements and tiers as well.
In another embodiment, the adaptable video architecture may provide for a scalable video pipeline. Video processing predicts the current frame content utilizing previous content from previous video frames. For example, H.264 uses this temporal coding for video processing. Other spatial and quality coding may also be used for video processing. Scalable video coding (SVC) is an extension of H.264 that uses video information at different resolutions to predict current frame content. SVC defines a plurality of subset bitstreams, with each subset being independently decodable in a similar fashion as a single H.264 bitstream. Merely by dropping packets from the larger overall bitstream, a subset bitstream can be exposed. Each subset bitstream can represent one or more of scalable resolution, frame rate, and quality video signal. More particularly, the subset bitstreams represent video layers within SVC with the base layer being fully compatible with H.264 (which is a single layer standard definition). When the overall bitstream is transmitted (e.g., by over air broadcast), a receiving device can use the appropriate subset bitstream to perform the video processing. The additional subset bitstream layers can be discarded or used to for temporal, spatial and/or signal quality improvements.
The adaptable video (transcode-encode-decode) architecture has at least two modes. First, the adaptable architecture is instantiated once for H.264 decode or other single layer standard. Second, the adaptable architecture is instantiated multiple times, each instance designed to accelerate the decoding of one SVC layer to improve the generated video image. For example, a lower resolution H.264 decode pipeline (M) may dump out internal aspects, which may then be read into next higher resolution layer (M+1). Information of values may be tapped out such as, e.g., motion vectors, transform coefficients, and/or image data prior to the application of the deblocking filter for use in the higher resolution pipeline. This may also be applied to multiple layers of progressively higher quality (and/or bitrate) at the same resolution or combined with different resolution layers. For example, a lower quality layer (e.g., signal-to-noise ratio or fidelity) may dump out internal aspects, which may then be read into next higher quality layer. The interlayer interpolations (e.g., up sampling and/or filtering) may be performed externally by software modules executed by shared general-purpose processing resources of the video device, or by dedicated hardware.
This may be extended to cover modalities to service multiple simultaneous streams, as well as (i) software only modes; (ii) sequential serial instantiation and use; (iii) cyclical serial flows; and (iv) a mix of (ii) and (iii). For example, in some implementations, a decoder may include a plurality of decode pipelines 103 (FIG. 1) with each decode pipeline 103 is associated with a different resolution. The decode pipelines 103 may be implemented in hardware and/or software modules executed by general-purpose processing resources. Information may be tapped out of a lower resolution decode pipeline (M), processed using an interlayer interpolation, and supplied to the next higher resolution decode pipeline (M+1) for use. In other implementations, a single decode pipeline may be used to perform the video processing at multiple resolutions. In this case, the decode pipeline 103 performs the video processing at a first resolution (M) with information being extracted as appropriate. The decode pipeline 103 may then performs the video processing at the next resolution (M+1) or at another higher resolution (e.g., M+2). Processing flow may be adjusted by sequencing the flow through the different decoding pipelines 103 as appropriate. In addition, encoder and transcoder pipelines may share some of the same functionality.
Referring to FIG. 3, shown is a flow chart illustrating an example of scalable video pipeline processing. Beginning with box 303 a video stream is obtained by a video device. The video stream includes a plurality of subset bitstreams that may be processed by, e.g., a video decode pipeline of the video device. A first subset bitstream having a first resolution is processed in the video pipeline of the video device in box 306. As discussed above, video information associated with the first subset bitstream is extracted (or tapped) from the video pipeline during processing of the first subset bitstream. In box 309, interlayer interpolation is performed on at least a portion of the extracted video information.
In box 312, at least a portion of the extracted video data is provided to a video pipeline of the video device for processing in box 315 of a second subset bitstream having a second resolution higher than the first resolution. In box 318, if another higher resolution subset bitstream is to be processed, then the flow returns to box 309 where interlayer interpolation is performed on at least a portion of the video information extracted during processing of the second subset bitstream. The flow continues until the processing of a higher subset bitstream ends at box 318.
In some embodiments, the adaptable video architecture may provide for pixel block size decomposition of the standard pixel block sizes defined by a standard. With reference to FIG. 4, shown is a flowchart illustrating the decomposition/recomposition of the standard pixel blocks. Beginning with box 403, an original pixel block may be decomposed into multiple sub-blocks which are fed through (decoding-encoding-transcoding) pipeline elements in box 406 before recomposing the results in box 409 to form a processed pixel block. Each sub-block may be processed by a different pipeline. Such multi-element pipelines may also be a single pipeline with multiple coding elements that happen to cycle on each sub-block before recomposition. In some cases, single element decomposition and re-composition may be achieved. Improved performance and efficiencies may be realized through the parallel processing of the sub-blocks.
It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure.

Claims

1-20. (canceled)

21. A device comprising:

at least one processor circuit configured to:

obtain an original pixel block of a video stream;

decompose the original pixel block into a plurality of sub-blocks;

process each of the sub-blocks through a plurality of pipeline elements, a first sub-block of the sub-blocks being processed through a first pipeline element of the plurality of pipeline elements and a second sub-block of the sub-blocks being processed by a second pipeline element of the plurality of pipeline elements that is distinct from the first pipeline element; and

recompose the processed sub-blocks to form a processed pixel block.

22. The device of claim 21, wherein at least one processor circuit is configured to process each of the sub-blocks through one of the plurality of pipeline elements in parallel.

23. The device of claim 21, wherein each of the sub-blocks is transcoded by the plurality of pipeline elements.

24. The device of claim 21, wherein each of the sub-blocks is processed through a different one of the plurality of pipeline elements.

25. The device of claim 21, wherein a third sub-block of the sub-blocks is processed through the first pipeline element after the first sub-block of the sub-blocks is processed through the first pipeline element.

26. The device of claim 21, wherein a size of the original pixel is indicated by a standard.

27. The device of claim 21, wherein the at least one processor circuit is further configured to:

receive a frame of the video stream;

separate the frame of the video stream into a plurality of original pixel blocks; and

obtain the original pixel block from the plurality of original pixel blocks.

28. The device of claim 27, wherein the at least one processor circuit is further configured to:

decompose each of the plurality of original pixel blocks into the plurality of sub-blocks;

process each of the sub-blocks of each of the plurality of original pixel blocks through the plurality of pipeline elements; and

recompose the processed sub-blocks of each of the plurality of original pixel blocks to form a plurality of processed pixel blocks.

29. The device of claim 28, wherein the at least one processor circuit is further configured to:

recompose the plurality of processed pixel blocks to form a processed frame of the video stream.

30. A method comprising:

obtaining an original pixel block of a video stream;

decomposing the original pixel block into a plurality of sub-blocks;

processing each of the sub-blocks through at least one pipeline element, the at least one pipeline element cycling through at least two of the sub-blocks; and

recomposing the processed sub-blocks to form a processed pixel block.

31. The method of claim 30, wherein the at least one pipeline element comprises a plurality of interconnected pipeline elements.

32. The method of claim 31, wherein a first pipeline element of the plurality of interconnected pipeline elements cycles through a first subset of the plurality of sub-blocks while a second pipeline element of the plurality of interconnected pipeline elements cycles through a second subset of the plurality of sub-blocks.

33. The method of claim 30, wherein the at least one pipeline element is configured to transcode each of the sub-blocks.

34. The method of claim 30, wherein a size of the original pixel is indicated by a standard.

35. The method of claim 30, further comprising:

receiving a frame of the video stream;

separating the frame of the video stream into a plurality of original pixel blocks; and

obtaining the original pixel block from the plurality of original pixel blocks.

36. The method of claim 35, further comprising:

decomposing each of the plurality of original pixel blocks into the plurality of sub-blocks;

processing each of the sub-blocks of each of the plurality of original pixel blocks through the at least one pipeline element;

recomposing the processed sub-blocks of each of the plurality of original pixel blocks to form a plurality of processed pixel blocks; and

recomposing the plurality of processed pixel blocks to form a processed frame of the video stream.

37. A computer program product comprising instructions stored in at least one non-transitory computer-readable storage medium, the instructions comprising:

instructions to receive an original frame of a video stream;

instructions to separate the original frame of the video stream into a plurality of original pixel blocks;

instructions to decompose each of the plurality of original pixel blocks into a plurality of sub-blocks;

instructions to process each of the sub-blocks of each of the plurality of original pixel blocks through at least one pipeline element;

instructions to recompose the processed sub-blocks of each of the plurality of original pixel blocks to form a plurality of processed pixel blocks; and

instructions to recompose the plurality of processed pixel blocks to form a processed frame of the video stream.

38. The computer-readable storage medium of claim 37, wherein at least two of the sub-blocks of at least one of the plurality of original pixel blocks are processed through the at least one pipeline element in parallel.

39. The computer-readable storage medium of claim 37, wherein the at least one pipeline element transcodes each of the sub-blocks of each of the plurality of original pixel blocks.

40. The computer-readable storage medium of claim 37, wherein a size of each of the plurality of original pixel blocks is defined by a video coding standard.