"The hard solution power consumption is much lower!" I believe this is the impression of most people on hard solution and soft decoding. However, how much is the specific low? A few people can give an answer. In order to uncover the mystery of this problem, the Peking University Digital Media Research Center specially used the power grid to test.
In terms of mobile video playback, the hard solution based on special chips has become the preferred solution for mobile video decoding due to fast speed and low power consumption. However, the hard-decoded chip deployment period is long, the iterative speed is slow, and the update speed of mobile video coding technology is quite extent. In recent years, with the continuous increase in intelligent handling capacity, software decoding is gradually being popular with convenient deployment. So, how much is the power consumption of hard solution relative to soft solution? With this problem, we chose several typical mobile phones to test H.264 / AVC hard solution, H.264 / AVC soft solution, H.265 / hevc hard solution, H.265 / hevc soft solution and AVS2 soft solution Differences in power consumption, discover an important phenomenon: hard solution is gradually lost relative to soft solutions, in recent years, smartphones produced in mainstream 720p (1280x720) and smaller resolution video on the video on the video The difference in power consumption is already small. This means that the update of mobile video coding technology will be greatly accelerated. The test processes and results are specifically described below.
Hardware decoding depends on terminal chips, smartphones generally support H.264 / AVC hardware decoding; mobile phones that support HEVC / H.265 hardware decoding are not fully popular, apple phones as examples, Apple mobile phones before IPHONE 6S do not support HEVC hard decoding; AVS2 is currently lacking hard solution support in the mobile terminal. In soft decoding, FFMPEG has built-in software decoding libraries for H.264 and H.265; our team developed AVS2 soft solution library -UAVS2D supported by mobile phone applications, you can implement smartphones real-time decoding 1080p video [1]. The power consumption of different soft hard solutions on different grades of mobile phones will be tested below.
1, test conditions
1) Test video
Test video includes 5 different scenes of video clips, cover interior scenarios, outdoor sports, natural scenery, interviews and other scenes. Test video is divided into three groups, with H.264, HEVC, and AVS2 encoding, three sets of video from the same video source, with the same resolution video coding quality. The specific video specifications are as follows:
2) Test model
3) Test tool
Power Test Tools: Monsoon Power Monitor AAA10F
Video Player: IJKPlayerDemo
Software decoder: FFMPEG built-in H.264 and HEVC decoder; UAVS2D decoder [2].
2, test method
1) Configure the test environment
a) Samsung S3: Remove the battery, Power Monitor supplies the phone and connects to the computer, sets the output voltage 3.7V, use the Main Channel test data.
b) iPhone: Connect the Power Monitor using a USB mode, full power status test charging power, and the charging power is approximately power consumption.
2) The mobile phone opens flight mode, connects to the WiFi network, clears all background processes, and the brightness is fixed to half of the maximum brightness, mute.
3) Keep the standby state first, waiting for the mobile phone power data to fluctuate smoothly.
4) conduct a set of tests
a) Start the power consumption tester record program;
b) Waiting for 100s to open a set of network test video (5 min);
c) The video playback is waiting for 100s;
d) Export power consumption data, calculate 100S average power consumption and video play for 5 minutes before and after calculation.
5) Repeat 4) Test five sets of data (H.264 hard solution, H.264 soft solution, H.265 hard solution, H.265 soft solution and AVS2 soft solution).
6) Replace the phone, repeat 1) -5), test Samsung S3, iPhone 6 Plus, iPhone 6s, iPhone 8 in turn.
3, test results
the data shows
1) Total power consumption refers to the mobile phone power power when video playback.
2) Standby power consumption means that the phone power consumption power when the mobile phone bright screen does not operate.
3) Test video is a network stream, the player is in advance because there is a data cache (15MB), the download is overhead, and the network download has a certain impact on power consumption.
4, test results analysis
With the improvement of intelligent handling capacity, the gap between soft and hard solution is gradually narrowed, for 720p video, IPHONE 8 H264 soft hard solution video play power consumption only 14%, while AVS2 soft solution scheme is only more than H264 hard solution Power consumption is 8%. Different software decoding schemes have a large difference in power consumption, and the AVS2 soft solution scheme is the lowest power consumption. Compared to the H.264 soft solution scheme, because the AVS2 compressed efficiency is higher, the same quality video, the AVS2 coded code rate can be less than 40% lower than H.264, lower code rate brings lower decoding complexity and network overhead. . Since we test the open source HEVC soft decoder, the calculation efficiency is general, so the power consumption of HEVC is relatively high.
Video resolution is larger than the soft solution power consumption, as shown in Table 2, as an example of iPhone 8, for 480P (640x480) video, AVS2 soft solution and H.264 hard solution power consumption; for 720p video, AVS2 soft Solution H.264 hard solution power consumption is 8%; for 1080p video, AVS2 soft solution is only 11% higher than H.264 hard solution consumption. It should be pointed out that the soft solution power consumption and the specific implementation scheme have great correlation. As the soft solution scheme continues to optimize, and the power gap between hard decoded power consumption is further reduced.
Summarize
With the universal computing power of smartphones, the mainstream mobile phone is currently in mainstream video resolutions such as 480p and 720p, the power consumption of soft solution and hard solution is small, which means that mobile video decoding supports support dependence on dedicated chips The speed of mobile video technology iteration will be greatly accelerated. , Read full text, original title: hard solution or soft solution? Mobile video playback power consumption
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