HD Video Playback
The low 3D performance of the new integrated graphics core of Atom CPUs is not really a big deal. Gaming capabilities are at the bottom of the wish list for an integrated CPU. A much more important and long-demanded capability is HD video playback. The Bonnell microarchitecture doesn’t have enough computing resources for that, but the graphics core with a specialized decoder may help in this case.
The graphics core of the first- and second-generation Atom CPUs had an integrated decoder to provide hardware acceleration for MPEG-2 video playback. This was insufficient functionality, so the Atoms made it into media players and multimedia computers only after being "ionized" by Nvidia's external GPU. It is only in the third Atom generation that Intel implements decoding of HD video in all popular formats, which is in fact the key reason for the introduction of the new GMA 3600 graphics.
Formally speaking, the new graphics core has everything necessary to play HD video. Its decoder supports hardware decoding of video in AVC/H.264, VC1/WMV9 and MPEG-2 formats. MPEG-4 part2 (Xvid codec) is not supported, though. The top bit rate the decoder can cope with is only 20 Mbps (according to the official specs). Still, this is a great step forward compared to the weak HD video decoding capabilities of the previous generations of Atom CPUs.
Indeed, these limitations are but a small nuisance compared to the problems on the software level which plague the GMA 3600.
Everything’s more or less normal while playing H.264 video.
The GPU takes on the bulk of work, offloading the CPU. There are no dropped frames. The image quality is okay, too. The bit rate is even higher than the specified 20 Mbps, but we don’t see any problems.
But the video in VC1 format could not be watched on the Cedar Trail platform at all. That’s all we could see:
Judging by the low CPU load, the hardware acceleration works, but it doesn’t work well. Besides our default player Media Player Classic Home Cinema 126.96.36.19935, we also tried the free VLC media player 2.0.1 and the proprietary CyberLink PowerDVD Player 12, but to the same effect.
The image quality problems will hopefully be resolved in the future versions of the software players but we don’t yet know when exactly.
We carried out a comparative test to check out the CPU load while playing HD video (1080p) in H.264 format on different energy-efficient platforms. Our software player was Media Player Classic Home Cinema 188.8.131.5235 and the test video had the following parameters: H.264, firstname.lastname@example.org, 23.7 Mbps.
The Atom D2500 is comparable to the AMD E-350, which is perhaps the best CPU for energy-efficient multimedia players, in terms of CPU load when playing video. The load level of the Atom N2800 is only half as high due to its Hyper-Threading technology.
Besides playing HD video in popular formats, the Cedar Trail should also be able to show high-definition video streamed via Flash-based players over the internet. We just tried to watch a 1080p clip from YouTube.com.
Well, the hardware acceleration works. The CPU load level is rather low and the player itself reports that it uses the graphics core resources to decode and render the video content. However, the frame rate is below standard and there are too many dropped frames. It means the GMA 3600 core cannot play high-quality video via Flash-based players. Well, the Cedar Trail platform is not officially supposed to accelerate HD video reproduced in this way.
Summing up the graphics capabilities of the new Atom platform, we must admit that, even though Intel has made a great step forward by replacing its own graphics core with a solution from Imagination Technologies in its energy-efficient CPUs, the result is far from perfect. Hardware acceleration only works for H.264 so far, the playback of the rest of HD video formats being plagued by various software and hardware flaws. It means that the Cedar Trail platform isn’t yet a good choice for multimedia players. We should wait at least for the most annoying of its bugs to be eliminated. Until then, the AMD Brazos is going to remain the best choice as an energy-efficient multimedia platform.