by Anton Shilov
01/23/2009 | 02:28 PM
High-definition video content (at resolutions of 1280x720 and higher) is becoming more and more widespread, and the GPU developers follow this trend by introducing innovations pertaining to the playback of such content. This trend is related to the increasingly more important role of the PC as an entertainment center at home and to the competition with the last generation of game consoles, Microsoft Xbox 360 and Sony PlayStation 3.
To name just a few innovations implemented by ATI, AMD’s graphics department, and Nvidia in their GPUs, there are the audio-over-HDMI feature, the hardware acceleration for decoding of video in H.264/MPEG4 AVC, VC-1 and WMV HD formats, post-processing of HD video, driver-integrated algorithms (very questionable ones) for enhancing the quality of HD video playback, etc.
Even inexpensive integrated graphics cores from AMD, Nvidia and even Intel have long acquired support for the HDMI interface (common in consumer electronics) and advanced video-processors, which indicates the developers’ interest in the HTPC concept (Home Theater Personal Computer).
Today, we will see how the HD video playback quality offered by the newest graphics cards has improved over the older GPUs and will measure the CPU load when watching high-definition movies. Besides graphics cards, our test session will cover the newest chipsets with integrated graphics cores: AMD 790GX, Intel G45 and Nvidia GeForce 8300.
You should keep it in mind that performance may not be the main factor for choosing the graphics solution for a HTPC. Such factors as compactness, moderate power consumption, HDMI support and others are highly important, too. Considering the abundance of differently designed graphics cards on the market, we will give you our general recommendations basing on the typical functionality of each graphics card series.
The war of the formats was won in early 2008 by Blu-ray technology promoted by Sony and Blu-ray Disc Association (BDA) after Toshiba had decided to give up its HD DVD because of the refusal of Warner Bros. to promote it. Warner Bros. is rumored to have received a few hundred million dollars of “incentives” from the interested parties for Blu-ray propaganda.
It had been suggested that the arrival of a single high-definition media format would facilitate its acceptance by the customer who wouldn’t have to choose between two formats. This has been true to some extent and the availability of Blu-ray movies in retail chains has become higher in the United States (fewer shelves are now dedicated to HD DVD) as well as in Europe (because the retailers hope to increase their turnover by selling expensive HD movies).
Unfortunately, the prices of Blu-ray players and drives have been declining very slowly. Sony, the developer of the standard, complained in November that its 2008 forecast about the annual sales of discrete Blu-ray players worldwide would not come true: 5.5 million devices would be shipped instead of the predicted 6 million. Anyway, Sony has something to be proud of: the sales of the Blu-ray-supporting game console PlayStation 3 have increased dramatically this year. It means that people now have far more devices with support of the new standard. However, many customers will hesitate before purchasing a movie in the new format because the price of Blu-ray titles is much higher than that of DVDs.
Besides the high pricing, there are more perils in Blu-ray’s way. There have appeared Web services offering video at resolution of 1280x720 (720p), which is far better than ordinary DVD (720x576 for PAL regions and 720x480 for NTSC regions) but worse than full-HD (1920x1080, 1080p). Besides, the worldwide economic recession has made people cut their costs, including entertainment costs.
But notwithstanding the temporary difficulties it faces as a standard, the Blu-ray format may have a bright future yet. Many optical disc makers have already demonstrated 400-500GB media which may enable a lot of breakthroughs and improvements in home cinema. As a result, Blu-ray may replace DVD and hold back the expansion of Internet video services, at least among movie lovers. Here are a few things we can expect from the evolving Blu-ray:
Thus, Blu-ray has got a lot of exciting things to offer to the customer. And although the future of the new standard is not without clouds, it will obviously be the etalon for all lovers of cinema and music for years to come.
The victory of Blu-ray in the war against HD DVD does not mean that the MPEG4 AVC/H.264 codec triumphs over VC-1, though. Many Blu-ray movies use the latter codec. Moreover, movies encoded with the MPEG2 HD codec are still available, too. Thus, all the three codecs must be supported by software and hardware manufacturers.
The Blu-ray and HD DVD standards brought two advantages: high resolution (up to 1920x1200) and high-quality audio (Dolby Digital True HD, DTS HD Master Audio, LPCM – Linear Pulse Code Modulation). These factors are going to eventually entice customers to buy movies in the new formats instead of DVD.
There are no limitations regarding video. All graphics cards with HDCP support can play protected Blu-ray/HD DVD movies at 1920x1080, but things are more complicated with respect to high-quality protected audio.
From a technical point of view, there is no obstacle to decoding the various lossless audio formats (DD TrueHD, DTS HD MA, etc) inside the PC and outputting them to the playback device via HDMI or simple analog connections. However, the output interfaces must ensure enough bandwidth, which may be a problem. Besides, no graphics card with HDMI support can output a protected audio track for further decryption and distribution among the audio channels by the hardware receiver because there is no protected audio path.
One way to solve this problem is to output an LPCM audio stream, which requires high bandwidth but no protection. Many studios include LPCM tracks into their Blu-ray releases, but the audio core must have specific functionality to be able to output such tracks to a receiver via HDMI. But if your configuration meets all the requirements, you will enjoy the best audio possible which will be distributed among the channels by your hardware receiver/amplifier.
An audio card capable of outputting audio over HDMI with support for a protected audio path may be another way to solve the problem.
A third method – which is the most obvious one for undemanding users – is to connect the audio equipment directly to the PC. This makes the option of outputting audio via the graphics card’s HDMI port a critical feature for most customers.
Today, the most advanced implementation of the audio-over-HDMI feature is available with ATI Radeon HD 4800/4600/4500 series cards. The integrated audio core from Realtek can output 7.1 audio (192kHz/24bits per sample) with a bit rate of 6.144Mbps in AC3, DTS, Dolby True HD, DTS HD and LPCM formats. Nvidia’s GeForce 8, 9 and GTX 200 series are limited by the capabilities of the S/PDIF interface and support 5.1 Dolby Digital, 5.1 DTS, and 2-channel LPCM. The integrated graphics cores Intel GMA 4500 and GeForce 8300 can output 7.1 LPCM audio, too.
Clearly, most HTPC users do not need an expensive receiver. Moreover, the majority of home cinema lovers do not have audio equipment capable of delivering the advantages of highest-quality audio tracks. They often use an analog connection between their sound card and the speaker system.
Considering the current state of the market, we’d recommend you to purchase a discrete sound card that has a HDMI output and supports as many standards as possible or install a Radeon HD 4000 series graphics card. But if you are not fastidious about the quality of audio, you should base your choice of the audio subsystem on your own preferences and resources.
It is important to know how much power your HTPC-oriented graphics card needs because this parameter is directly linked to its temperature and noisiness. We performed our measurements on the following testbed:
The 3D load was created by means of the first SM3.0/HDR test from 3DMark06 running in a loop at 1600x1200 with 4x FSAA and 16x AF. The Peak 2D mode was emulated by means of the 2D Transparent Windows test from PCMark05. This test is important as it simulates the user’s working with application windows whereas Windows Vista’s Aero interface uses 3D features. We got the following results:
As you can see, the power consumption of graphics cards is directly proportional to their performance in games. Although the Radeon HD 4850 is a very fast solution, it needs as much as 110 watts of power under load. Therefore it may only suit a gaming-oriented HTPC with good ventilation.
We guess the Radeon HD 4670 has the optimal ratio of power consumption to performance in games and during video playback whereas the Radeon HD 4550 is the most economical and smallest card today.
Most of the graphics cards covered in this review are available with different cooling systems, so there is no sense in comparing the noisiness of the reference coolers. The HTPC concept implies that you adjust your computer to your specific goals, so it wouldn’t be right for us to recommend some specific graphics card models to you here.
We checked out the image quality and graphics processors performance during video decoding and playback on the following platform:
Below is the list of graphics cards and integrated solutions participating in out today’s test session:
Since HTPC users are very unlikely to install a noisy and expensive graphics accelerator into their systems and since many newest solutions such as ATI Radeon HD 4870/4870 Х2 and Nvidia GeForce GTX 260/280/285/295 do not fit into our Antec Fusion case, we will not be discussing high-end products today.
Mainboards with integrated graphics core for AMD processors were tested with the similar software and hardware components with that only difference that we used an AMD Phenom X4 9550 processor. Since it is quad-core CPU, integrated AMD platforms demonstrate significantly higher results than the competitor solutions.
We used the following tools to estimate the video playback quality in standard (SD) and high-definition (HD) resolutions:
The driver settings remained the same. However, according to the HQV HD suite requirements, the noise suppression and detail levels for Nvidia GeForce graphics cards and Intel Graphics Media Accelerator 4500 were set to the maximums.
Keeping in mind that all tests are run under Windows Vista OS without disabling background services, the CPU utilization peaks shouldn’t be regarded as critical. It is much more important how much time it takes the CPU on average to complete the task. Note that the CPU utilization may vary. Therefore, 1-2% difference is not indicative of any advantage of a certain graphics accelerator over the competitor.
Since MPEG2 decoding and DVD playback are no longer a complicated task for GPUs, we didn’t measure the CPU utilization in this case.
To estimate the CPU utilization during full-HD video playback (1920x1080) and full-HD video with enabled “picture-in-picture” feature, we used the following movies:
Since there is also a lot of HD content available online these days, we also measured CPU utilization during playback of several free videos with the following parameters:
The HQV benchmarks from Silicon Optix, the leading developer of video processors for home video players, are one of the few available methods of evaluating the playback quality of Blu-ray, DVD and HD DVD movies. They have one drawback, however. The tester’s perception is subjective while the notion of an ideal picture is rather vague.
We have been criticized for following the HQV HD test instructions too closely and giving out too low scores. However, our scores seem to have been quite correct because some GPU’s playback quality has improved dramatically over time.
The three major developers of graphics solutions, ATI/AMD, Intel and Nvidia, are constantly optimizing video playback settings in their drivers, so the playback quality in general and the HQV HD result in particular have increased over the last year. Alas, ATI and Nvidia do not take the HQV test seriously as the lowering results indicate.
So, considering the subjective nature of this test, you should not view the HQV and HQV HD results as the ultimate truth.
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Although DVD has become obsolete and even, for some people, dead with the arrival of HDTV and Blu-ray/HD DVD, not all modern GPUs can play that old format at high enough quality.
None of the tested GPUs could achieve the maximum score of 130 points. The main problems are the inability of the GPUs to smooth out the jaggies and transform filmed content (24fps, progressive scan) into DVD or 1080i HDTV with the 3:2 pulldown method. For some reason, some GPUs prove to be unable to render text over video, which is a serious problem.
Standard-resolution video is dying out. The TV channels in the United States are already broadcasting in 720p whereas HTPC owners are going to use full-HD TV-sets with a resolution of 1920x1080. As a result, it is far more important to ensure high-quality playback of high-definition video.
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As you can see, many GPUs boast exceptional quality. In fact, nearly every mainstream and performance-mainstream GPU is very good at playing Blu-ray and HD DVD movies. The disappointing results only come from the integrated graphics cores Intel GMA 4500 and Nvidia GeForce 8300, and from the discrete Radeon HD 3400.
We want to note that no GPU could reproduce the Film Resolution Loss Test - Stadium with 100% correctness. The GPUs that received 10 points for that test had no moiré but had some flickering. If you feel like fault-finding, you should subtract these 10 points from the total score because, according to the HQV HD instructions, flickering means 0 points.
Another thing we must note is that Nvidia’s GeForce processors are still inferior at reducing noise to ATI’s Radeon HD chips.
With a single exception, ATI Radeon GPUs have lower CPU load than Nvidia’s GeForce GPUs due to the hardware deficiencies of the latter (they lack bitstream processing for the VC-1 codec).
Our testbed has a fast CPU. If you’ve got a slower model, you should choose your graphics card carefully: where our CPU needed 40% of time to help decode VC-1, a weaker CPU may take much more time, which may result in the loss of frames in complex dynamic scenes, especially when you enable Picture-in-Picture mode/Bonus View.
As opposed to VC-1, there are no clear winners or losers when it comes to decoding MPEG4 AVC/H.264. The average CPU load varies within 20-25%, which is rather low.
Interestingly, for many GPUs that offer hardware acceleration for two streams simultaneously, the task of decoding a scene from The Day After Tomorrow with a very high bit rate (a distinguishing feature of all movies from Fox Home Entertainment) proved to be more difficult than the reproduction of the last scene from Beowulf with Picture-in-Picture mode enabled.
We did not test the CPU load when playing MPEG2 video although Blu-ray movies encoded with MPEG2 HD are available on the market. If you’ve got such discs, you may be interested to know the CPU load when decoding MPEG2 stream at 20-25Mbps (a free clip from NASA showing a space shuttle launch).
Notwithstanding its indisputable popularity, the DivX codec has never been a favorite of hardware developers. When it just appeared, DivX-encoded movies and clips would be slow on low-end PCs. Today, GPUs offer almost no support for DivX decoding, either. As a result, if you’ve got HD movies encoded with DivX, you have to buy a fast CPU to achieve good playback.
The Intel GMA 4500 ensures the lowest load of our dual-core CPU (46.9%) whereas the highest load (66.2%) can be observed with the Radeon HD 3870.
Considering the long life of MPEG2 format and the fact that a MPEG2 decoder is integrated into every modern GPU, there is no wonder that we have good results when playing MPEG2 clips and movies at 1920x1080. None of the tested GPUs required more than 20% of the CPU’s time when decoding the 1080i stream.
MPEG4 AVC/H.264 is popular not only among official content distributors but also among the distributors of HDTV rips of various sitcoms such as Lost or Prison Break. The consequence of this popularity is that the GPU developers implement hardware H.264 decoders into their products. As you can see, a typical 720p stream (1280x720) can be decoded on the GPU alone.
Our 720p clip encoded with VC-1 has a frame rate of 60fps, requiring a lot of resources to play.
As you can see, some GPUs, the Radeon HD 4670 and Radeon HD 3870, require more than 50% of the CPU time on average to decode this clip. That’s quite a lot. Most of the tested GPUs require about 40% of the CPU time, which is high, too.
The best result belongs to the Intel GMA 4500 core which needs only 34.1% of time of our dual-core processor whereas the Radeon HD 4670 and HD 3870 have the worst results (52.9% and 52%, respectively).
WMV HD is getting less popular due to its successor VC1, yet we tested this format, too. The graphics cards have about the same level of CPU load. The Radeon HD 4000 seem to be somewhat worse than the others, though.
Nearly every modern GPU is effective at decoding high-definition video. However, the playback quality may vary greatly even within the same GPU series.
Our tests show that despite the 12-year-long tenure of the DVD standard on the market none of the graphics cards can boast maximum playback quality with it.
ATI’s Radeon HD 4800/4600 and Nvidia’s GeForce 9600 GPUs deliver the best image quality in the Silicon Optix HQV test (118 out of 130 points). The Radeon HD 3800 and GeForce 9800 are but barely worse, scoring 116 out of 130. Surprisingly, the Intel GMA 4500 processor is almost as good as the discrete GPUs, scoring 113 out of 130 points. The GeForce 8300 IGP and GeForce 8500/9400 GPUs are a disappointment as they could score only 80 points.
The quality of HD video playback on today’s PCs is also questionable, according to the Silicon Optix HQV HD. ATI’s Radeon HD 4800/4600/4500 cards deliver an ideal picture (100 out of 100 points) whereas ATI’s Radeon HD 3800/3600 and Nvidia’s GeForce 9800/9600 are very close to that (90 out of 100 points). The integrated Radeon HD 3300 is good (80 out of 100) whereas the results of the Radeon HD 3400, GeForce 8300 and Intel GMA 4500 (65, 60 and 50 points, respectively) are simply disappointing.
Of course, the playback of high-quality Blu-ray movies (The Day After Tomorrow, Transformers, Casino Royale) is going to be top class even on the Intel GMA 4500, but there are a lot of movies that need noise reduction (28 Weeks Later) or detail enhancement (The League of Extraordinary Gentlemen). If these features do not work properly, watching such movies won’t be a pleasure.
We must note one thing here. Practice suggests that modern GPUs can be reprogrammed to deliver much higher video playback quality. Therefore, the current situation can change in the future. But right now, ATI’s Radeon HD 4800 and 4600 GPUs are the best in terms of DVD, Blu-ray and HD DVD playback.
Our tests showed that the CPU load was low with every graphics card when we decoded typical video content. In other words, any of the tested cards is going to be good for a HTPC in terms of video playback performance unless you have some specific requirements.
However, we’d recommend you to install a fast CPU into your system if you are going to play DivX HD or videos with an increased frame rate. Modern GPUs do not accelerate DivX HD whereas 60fps clips provoke a high CPU load.
Nvidia’s GeForce 8/9 GPUs do not offer hardware bitstream processing for the VC-1 codec and have a somewhat higher CPU load when playing VC-1 videos than ATI’s Radeons have. But the higher CPU load shouldn’t be a problem for a desktop PC. We guess that only cheap GPUs like GeForce 8500/9400 coupled with a slow CPU won’t be able to cope with complex scenes and you’ll have skipped frames or slow audio then.
So, we have identified those cards that deliver the highest quality when playing different video content and reduce the CPU load. We have also found out that the HDMI-supporting graphics cards offer different level of support for the audio-over-HDMI feature. It’s time for us to give you some shipping advice about choosing the graphics card for a HTPC.
Playback quality was our priority when we preferred a specific graphics card. But considering the specific requirements (e.g. power consumption), we’ve written a list of several graphics cards that can be viewed as the best options for a HTPC.
The most advanced HTPC-ready graphics cards in terms of gaming performance:
The most economical HTPC card:
The most appealing chipset with an integrated graphics core: