Performance Specifications
This section describes only the performance specifications of Ascend AI Processors of each product, which may differ based on the memory and CPU configurations of the respective product. For details about the product performance specifications, see the official descriptions at the Ascend community.
This section uses a single Ascend AI Processor as an example to describe the performance indicators in basic scenarios. The performance indicators of other resolutions can be estimated in the same way.
In the following table, one channel corresponds to one thread, 720p indicates a resolution of 1280 x 720 pixels, 1080p indicates a resolution of 1920 x 1080 pixels, and 4K indicates a resolution of 3840 x 2160 pixels.
Performance Specifications (Atlas 200/300/500 Inference Product)
- The recommendations on channel count (n) in typical single-device VDEC scenarios are as follows.
Table 1 Performance specifications of the Ascend AI Processor on the Atlas 200/300/500 Inference Product Resolution
Total Frame Rate
Per Channel Frame Rate (n Channels)
Max Memory Usage per VDEC Channel (Using H.265 Input Streams with Nine Reference Frames as an Example)
4K
120 FPS
120 FPS/n (n = 4 is recommended, 30 FPS per channel.)
About 182 MB
1080p
480 FPS
480 FPS/n (n = 16 is recommended, 30 FPS per channel.)
About 56 MB
≤ 720p
960 FPS
960 FPS/n (n = 32 is recommended, 30 FPS per channel.)
About 35 MB
The following table uses 1080p input streams as an example to describe the formula for calculating the maximum memory used by each VDEC channel. The memory usage is calculated as follows:- Buffer size for the input streams: 6 MB when resolution ≤ 1080p; 9 MB when resolution > 1080p.
- Frame buffer size for the decoded images: 3 MB when resolution = 1080p. For other resolutions, convert the value proportionally.
- TMV buffer size for the decoded images: 0.5 MB for H.264, 1080p input streams; 1 MB for H.265, 1080p input streams. For other resolutions, convert the value proportionally.
- Number of reference frames: The maximum number of reference frames is used as an example. The system adapts to the actual number.
Formula
Scenario
Memory Usage
4 MB + Buffer size for the input streams x 2 + (Frame buffer size for the decoded images + TMV buffer size for the decoded images) x (Number of reference frames + 1)
- Input stream format: H.264
- Input stream resolution: 1080p
- Buffer size for the input streams: 6 MB
- Frame buffer size for the decoded images: 3 MB
- TMV buffer size for the decoded images: 0.5 MB
51 MB (nine reference frames)
26.5 MB (two reference frames)
- Input stream format: H.265
- Input stream resolution: 1080p
- Buffer size for the input streams: 6 MB
- Frame buffer size for the decoded images: 3 MB
- TMV buffer size for the decoded images: 1 MB
56 MB (nine reference frames)
28 MB (two reference frames)
- Suggestions on the number of decoding channels and frame rate:
The specifications in the following table are for reference only. If the number of channels started in a single process exceeds the specifications in the following table, memory insufficiency or performance drop may occur, leading to decoding channel creation failures and slow decoding.
- 720p indicates a resolution of 1280 x 720 pixels.
- 1080p indicates a resolution of 1920 x 1080 pixels.
- 4K indicates a resolution of 3840 x 2160 pixels.
Typical Resolution
Suggested Channel Count per Process (Based on the Input Frame Rate)
-
Input frame rate ≥ 25 FPS
20 FPS < Input frame rate < 25 FPS
15 FPS < Input frame rate ≤ 20 FPS
10 FPS < Input frame rate ≤ 15 FPS
Input frame rate ≤ 10 FPS
≤ 720p
32 channels
32 channels
32 channels
32 channels
32 channels
1080p
16 channels
19 channels
24 channels
32 channels
32 channels
4K
4 channels
4 channels
6 channels
8 channels
12 channels