Intel Quick Sync Video
Intel Quick Sync Video is Intel's hardware video encoding and decoding technology, which is integrated into some of the Intel CPUs. The name "Quick Sync" refers to the use case of quickly transcoding ("syncing") a video from, for example, a DVD or Blu-ray Disc to a format appropriate to, for example, a smartphone. Quick Sync was introduced with the Sandy Bridge CPU microarchitecture on 9 January 2011.
Quick Sync has been praised for its speed. Eighth Annual MPEG-4 AVC/H.264 Video Codecs Comparison showed that Quick Sync is comparable to x264 superfast preset in terms of speed, compression ratio and quality (SSIM); tests were performed on Core i7 3770 (Ivy Bridge) processor. A benchmark from Tom's Hardware showed that Quick Sync could encode a 449 MB, four minute 1080p file to 1024×768 in 22 seconds. The same encoding using only software took 172 seconds but it is not clear what software encoder was used and how it was configured. The same encoding took 83 or 86 seconds GPU-assisted, using a Nvidia GeForce GTX 570 and a AMD Radeon HD 6870 respectively, both of which are contemporary high end GPUs. Unlike video encoding on a general-purpose GPU, Quick Sync is a dedicated hardware core on the processor die. This allows for faster and more power efficient video processing.
Quick Sync, like other hardware accelerated video encoding technologies, gives lower quality results than with CPU only encoders. Speed is prioritized over quality.
Quick Sync development
Quick Sync was first unveiled at Intel Developer Forum 2010 (13 September) but, according to Tom's Hardware, Quick Sync had been conceptualized 5 years before that. The older Clarkdale micro-architecture had hardware video decoding support, but no hardware encoding support. known as Intel Clear Video.
- Generation 1 (Sandy Bridge)
- Quick Sync was initially built into some Sandy Bridge CPUs, but for example not on some low-end Sandy Bridge Pentiums or Celerons.
- Generation 2 (Ivy Bridge)
- The Ivy Bridge micro-architecture included a "next generation" implementation of Quick Sync.
- Generation 3 (Haswell)
- The Haswell micro-architecture implementation was focused upon quality, with speed about the same as before (for any given clip length vs. encoding length). It has seven hard-coded quality/performance levels (called "target usages"), compared to the three in previous generations. The highest-quality TU1 setting is intended to be higher quality than Ivy Bridge's version, and the highest speed TU7 setting should be faster, higher-quality, and more battery-friendly for mobile devices.
- The current generation of Quick Sync supports the H.264/MPEG-4 AVC, VC-1 and H.262/MPEG-2 Part 2 video standards.
Operating system support
The Quick Sync Video SIP core needs to be supported by the device driver. The device driver provides one or more interfaces, for example VDPAU, VAAPI or DXVA for video decoding, or OpenMAX IL for video encoding. One of these interfaces is then used by end-user software, for example VLC media player or GStreamer, to access the Quick Sync Video hardware and make use of it.
Microsoft offers a wide support for Quick Sync in Windows based on supporting driver software from Intel and good support through both DirectShow/DirectX as well as WMF (Windows Media Foundation). A wide range of applications are based upon this base support for the technology in Windows. Windows support is available from Windows Vista onward.
Support for Quick Sync hardware accelerated decoding of H.264, MPEG2, and VC-1 video is widely available today. One common way to gain access to the technology on the Microsoft Windows platform is by use of ffdshow filter produced by Eric Gur, an Application Engineer at Intel. However many commercial application also benefits from the technology today.
It has been claimed that in testing it keeps the CPU at its lowest possible frequency to reduce power consumption to maximize battery life for mobile devices while being about twice as fast as libavcodec.
Also support for hardware assisted media encoding tailored for Quick Sync is widely available today. The process of encoding media (from a raw, uncompress format to a compressed format, for Quick Sync h.264) and transcoding media (from one compressed format to another) is a rather resource consuming one. Many times this task will be so consuming that a general purpose CPU will not even be able to do this in real time (or even close). This is where technology specialized at decoding and encoding comes in handy and enables this task in a very enhanced way.
Examples of such software with Quick Sync support during encoding processes are Badaboom Media Converter, Cyberlink MediaEspresso, ArcSoft MediaConverter, XSplit Broadcaster, XSplit Gamecaster (all commercial) and projects like HandBrake (windows beta build only) or Open Broadcasting Software.
- Intel Clear Video, video decoding using a general purpose Intel GPU.
- Video Codec Engine, AMD's equivalent technology
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