H.264
From esoterum.org
Contents
Trading power for PSNR
Modifying the Encoder
- In contrast to the original proposal, we would like to look at modifying the encoder in order to make decisions about which blocks to drop. In this case, the decoder need only decide how many blocks to drop. The encoder would categorize and arrange the blocks in the stream so that the "important" blocks are sent first, enabling the decoder to drop the last n blocks without even decoding them.
- One issue to be addressed in the encoder: how do we decide which blocks are more important? Currently the idea is to look at blocks with smaller motion vectors and consider those less important. An important issue which arises is that this might prevent large slow moving objects from moving at all in the image. This might be avoided if the encoder looks at the average vector size, or vector statistics in order to avoid this situation.
Modifying the Decoder
- Enabling energy reduction functionality in the decoder without the benefit of a specialized encoder to first analyze the data poses some problems in terms of energy conservation. We want to reduce the amount of computation in order to throttle the processor, but the overhead required to make block dropping decisions might alleviate the advantage.
Benchmarks
- Media benchmarks including H.264, not yet for SimpleScalar
- SimpleScalar benchmarks, mpeg2 only
Applicability to Bistable Displays
Articles
- C. Lian, S. Chien, Chia-ping Lin, P. Tseng, L. Chen, "Power-Aware Multimedia: Concepts and Design Perspectives", Circuits and Systems Magazine, IEEE, 2007, Volume: 7, Issue: 2, page(s): 26-34
- T. Shih, C. Yang, and Y. Tung, "Workload Characterization of the H.264/AVC Decoder", Book Advances in Multimedia Information Processing pp. 957-966, PCM 2004.
- A. R. Iranpour and K. Kuchcinski, "Performance Improvement for H.264 Video Encoding using ILP Embedded Processor", Proceedings of the 9th EUROMICRO Conference on Digital System Design (DSD'06).
