That's the job of video codec software.
With 4K content,which has four times the resolution of HD, there is a need for new codecs that can deliver the quality of Ultra HD content, yet compress it down so all that data can fit within the bandwidth of people's home Internet connection and perhaps onto discs someday.
With the VP9 codec, Google is working to fill that void. VP9 is a new video codec that will compress video files to half the size that the current encoding technology, called MPEG-4 or H. More important, it will be used to compress video files and streams at 4K resolution, which is four times higher than HDTV resolution.
VP9 is part of WebM, an open-source project sponsored by Google for creating technology for use with media on the Internet. A codec an abbreviation of the term "coder-decoder" is software that uses an algorithm to systematically compress raw video data into a compact form fit for efficiently broadcasting, transmitting over an Internet stream or storing on a DVD or Blu-ray disc, for example. Without a codec, there simply wouldn't be enough bandwidth or storage space for HDTV to be possible.
Force YouTube to Stream H.264/AVC with h264ify
At the receiving end, the same codec in your TV, computer or disc player uncompresses the data to display the video on your screen. Codecs also remove some detail from video to reduce its size, and a high level of compressions can noticeably degrade image quality.
Most pay-TV services use aggressive compression to get all those channels into your cable or satellite receiver, which is one reason the video from your cable box does not look as good as that from a Blu-ray. A good codec will compress video down while causing few defects due to overcompression. High-definition video can take a lot of data.
A full-HD image has about 2 million pixels and potentially millions of colors making up an individual frame, with hundreds of thousands of frames making up a movie. Those high-definition images are in either p resolution x pixels, or 0. The images from a video in the 4K format, also known as Ultra HD, have about 8.
The end of the 4k war between Youtube and Safari?
Such a huge jump in detail requires a better way to compress the data in order to transmit or store it. VP9 is twice as efficient as H. The result is that current HD content will need only half the data to be streamed, and streaming 4K content will be viable. Google is ostensibly responsible for the creation of the VP9 codec and has already announced it will be used for 4K content on YouTube.
It will also likely be used by the Google Play streaming video service. Each individual service will have to decide whether to start sending data using VP9 instead of the current H.I reported on some quick and dirty comparisons at Streaming Media West and expanded upon those for this article. The short answer is that the quality produced by each codec is very similar. I selected three 4K source clips. The first, which I called the New clip, was a collection of footage I shot with a RED camera for a consulting project; this clip is designed to represent real-world footage.
The second was a short section from Blender. The third was a short section from Blender. These mezzanine clips were the starting points for all encodes. All three companies encoded clips to my specifications and supplied them to me. I also contacted MainConcept, which supplied a copy of its flagship encoder, TotalCode Studio, and advised me to use the standard presets modified for the appropriate resolution, data rates, and frame rates.
I quickly learned that TotalCode has two limitations. The second limitation is that the encoder currently supports only single-pass encoding. Once I received or created all the test clips, I confirmed that they met the data rate limits, then compared their respective video quality measurement VQM scores using the University of Moscow Video Quality Measurement Test.
You can see the results in Table 1with lower scores being better. The three columns on the left show the results from the three HEVC participants with VP9 the last column on the right. The lowest and best score for each clip is highlighted in green, and the average score for each technology is shown in the total row at the bottom of the table. As you can see, VP9 scored the lowest and best of all tested codecs, though the difference between x and VP9 was negligible and commercially irrelevant, as was the difference between x and the IP Provider.
After running the objective tests, I viewed each clip in real time to observe any motion-related artifacts that might not have been picked up in the objective ratings. I saw nothing during these trials that contracted the objective VQM findings.
The Great UHD Codec Debate: Google's VP9 Vs. HEVC/H.265
Regarding MainConcept, the ratings are not surprising, since the current version of TotalCode Studio only supports single-pass encoding. Since the clips were produced using percent constrained VBR encoding, this meant that technologies with two passes could allocate more data to the hard to encode regions in all test clips. As an example, Figure 2 shows how MainConcept compared to x over the duration of the x New clip, with MainConcept in blue and x in red. Lower scores are better.
As you can see, the quality of the two codecs was very similar except for the region on the extreme right: the high motion, high detail shot shown in Figure 1 that was the hardest to encode in the entire clip. With the benefit of two-pass encoding, TotalCode Studio could have allocated more data to this region, which likely would have resulted in much closer scores.
Figure 2. MainConcept proved very close to x in all but the highest motion regions of the clip MainConcept is blue, x red, lower is better. As a complement to the main testing, I encoded a talking head clip with consistent motion throughout with both codecs x and MainConcept, testing the theory that consistent motion would negate the benefit of two-pass encoding. Despite the two-pass encoding advantage enjoyed by x, MainConcept won this trial with a VQM score of 0.
In addition, in the single-pass encoding trials I ran for the aforementioned HEVC configuration story, MainConcept was slightly ahead in most tests. It's more efficient than H. For compressionists who want to see the image quality differences a tool measures, SSIMWave can feel incomplete.
An upcoming update may change that. While it's fun to be on the cutting-edge of new video codecs and formats, H. Why did Google purchase On2 Technologies back in ?
Because encoding and streaming VP9 video is saving it tens of millions each year.VP9 is an open and royalty-free  video coding format developed by Google. Parts of the format are covered by patents held by Google. The company grants free usage of its own related patents based on reciprocity, i. Mozilla added VP9 support to Firefox in March In an updated version of the WebM format was published, featuring support for VP9 together with Opus audio. In Marchthe MPEG Licensing Administration dropped an announced assertion of disputed patent claims against VP8 and its successors after the United States Department of Justice started to investigate whether it was acting to unfairly stifle competition.
Throughout, Google has worked with hardware vendors to get VP9 support into silicon. In April Google released a significant update to its libvpx library, with version 1. VP9 support was added to Microsoft's web browser Edge.
In MarchIttiam announced the completion of a project to enhance the encoding speed of libvpx. VP9 is customized for video resolutions greater than p such as UHD and also enables lossless compression.
The VP9 format supports the following color spaces : Rec. An early comparison that took varying encoding speed into account showed x to narrowly beat libvpx at the very highest quality slowest encoding whereas libvpx was superior at any other encoding speed, by SSIM. Another decoder comparison indicated 10—40 percent higher CPU load than H. VP9 offers the following 14 levels: . VP9 is a traditional block-based transform coding format.
The bitstream format is relatively simple compared to formats that offer similar bitrate efficiency like HEVC. VP9 has many design improvements compared to VP8. This is especially useful with high-resolution video. In order to enable some parallel processing of frames, video frames can be split along coding unit boundaries into up to four rows of to pixels wide evenly spaced tiles with each tile column coded independently.
This is mandatory for video resolutions in excess of pixels. A tile header contains the tile size in bytes so decoders can skip ahead and decode each tile row in a separate thread.
H.265 vs VP9: 4K video codecs explained
Subunits are coded in raster scan order: left to right, top to bottom.In this part, we tested the lossy compression capability. To measure the fidelity of the reconstruction encoded video of lossy compression codecs in our tests, we used PSNR Peak signal-to-noise ratio. The greater the PSNR of two videos, the more similar they are. If the encoded video is lossless, the PSNR will be infinity when compared to the original. We tried to match the PSNR and compared the video stream size, the smaller the size, the better the codec.
But it is hard to make the PSNR exactly the same. As mentioned earlier, as of Junethe AV1 is still experimental and we were not able to set its constant quality mode as we expected. And AV1 is extremely slow. So we did the AV1 in its vibrate bitrate mode first. We have found that the VP9 produces better results when encoded in its 2-pass constant quality mode can be set with "-crf"so we chose that.
But the VP9 will round any decimal number of "crf" to an integer, that is to say, it can not be adjusted precisely, so we ended up with encoded videos with slightly different PSNR. Do you think that high resolution or framerate would change the standings? Its an advantage. The issue is decoding speed. Encoding isnt as big an issue, even if a 2 hour movie takes 2 weeks to encode, usually you just have to do that once if youre competent with settings. Post a Comment. But in test 1, x is the winner.
The video encoded with AV1 is smaller than the video encoded with x, but not that impressive. This may be because the source video has many still sessions with a black background, and as we have learned from part IAV1 doesn't do as well in lossless compression. And the scenes change so fast that it limits the reuse of blocks.
AV1 is even slower than in part I, our lossless test, being approximately x slower than x VP9 and AV1 can take advantage of multi-threading, but they can not load all CPU cores all the time as x and x do. We used x as the HEVC encoder. All encoders were tuned for PSNR, except settings mentioned above and "crf" or "vbr", all other settings were as default. Laura Bush April 17, at PM. Paultimate February 7, at PM.
For Intel's 7th and 8th generation processors, the only Windows operating system that Intel supports is Windows 10 x There is no official driver for Windows 7, Windows 8, or Windows 8. The graphics driver for 6th gen proce…. Read more. ConclusionIn terms of lossless compression, x and x took less time and produced smaller files. In our tests, AV1 takes approximately x more time than x to encode in their lossless mode.
AV1 does have a lossless mode, but the output is not lossless at all.Log in or Sign up. Steve Hoffman Music Forums. YouTube sound quality? And do the video quality settings affect it? I don't mean the quality of the original recordings, which could be anything from needle drops to dubs from old cassettes to compressed and distorted live cell phone recordings. But I was listening to some old ABBA demos and wondered about YouTube sound quality, and if higher quality video carried higher quality audio, and got more curious when Googling yielded contradictory answers.
So what IS the current status? Location: South Mountain, NC. It's all over the map. It's not You Tube per se, but the quality of the encoders used to generate the videos. Typical quality is mp3, brickwalling at 15 kHz.
I've also seen it die at 10 kHz, I've seen a bizarre trough at kHz, and also smooth right up to 20 kHz. The "quality" setting has to do with the video resolution, not audio.
That's what I've seen, anyway. JBStephensApr 2, Location: United States. It can sound fairly decent if the audio is given care during the encoding process, but most people are re-encoding low-bitrate MP3s which then get re-re-encoded to YouTube's file format. MichaelXX2Apr 13, The FRiNgE likes this. Location: Dayton, OH.
I'm sure what's been said is all true. Generally speaking however, you won't get better sound quality unless you go to a higher video rate. I usually try to play back at p or The rate slows my computer down too much and the video stutters. Many times though, in regards to sound quality on Youtube, the saying "you can't polish a turd" comes to mind.
Too many people just don't care or aren't technically proficient enough to get it right. Digital-GApr 13, Location: Buenos Aires, Argentina.
The PinheadApr 13, Location: Wappingers Falls NY. Last edited: Apr 13, Youtube sound quality is dependent on your internet speed Some files are m4a while others are ogg opus and vorbis. It turns out we're all mostly wrong and that it depends on the date of the upload. Sound quality used to be much better which is surprising. Location: New England.This news made me excited. I normally watch Youtube at least one hour daily.
On my 43 inch 4k monitor, these landscape scenery video made me feel like real. Someone even posted a 8k 60fps video on Youtube. For example, playing this 8k video on Chrome looks like this:.
But on Safari, I cannot even play 4k resolution. So I did some research. From January, Youtube uses only VP9 codec, which is from Google, on all the video with higher resolution than 4k. That is to say, Safari only support up to p Youtube video. Here is a Youtube engineering blog, explaining why they use VP9. There are some samples in this blog, comparing VP9 and h. In a word, under the same bitrate, h. On Safari, I opened a p video, the mime type is mp4, codec avc.
Actually, except you cannot play 4k video from Youtube in Safari, for non-4k videos, the audio is also different from Chrome. Safari has more background noise. Someone may ask, why I have to play 4k video on Safari? Personally, I prefer Safari for the better and smoother experience in Mac. And now Safari has picture-in-picture feature, which is difficult to be achieved in Chrome. If I have to play 4k Youtube on Safari, there is a walk-around.
Then on Safari, finally there is a 4k option.VP9 - VP8 - H.265 - x264 encoder test
But, in this case, there is no speed up option. And, this extension is not stable. Not true, since Youtube does NOT support h.Trusted Reviews may earn an affiliate commission when you purchase through links on our site. Learn More. They are competing next generation video compression formats that claim to be twice as efficient as H.
They also halve the file size of p and p content making it far easier to download or stream HD video over slow connections. It was approved as the official successor to H.
Like H. By contrast VP9 is open source and royalty free. It was developed by Google as a successor to VP8, the moderately successful alternative to H. By doing the opposite of what you might expect. While 4K video increases picture quality by making individual pixels smaller, effectively what H. It then performs a vast array of processing tricks on the video as it is played to get the detail back. For context H. VP9 is similar on the surface. On the flip side it only has 10 prediction modes to rebuild them.
Cynics argue VP9 changes H. Needless to say both standards require more computational power than H. The first thing to say is we are greatly simplifying these formats, but — despite similar file sizes — initial reports suggest H.
The greater prediction modes in H. Previously this made H. This time around things are closer. The flip side is all these companies have also backed H. With the decline of physical media and the rise of 4K Ultra HD, there has never been greater pressure on new video compression standards to deliver. Thankfully both do, if in slightly different ways, and — unlike past format wars — there is likely to be space for both as the industry seems reluctant to wholly commit to a a future paying license fees, or b being beholden to Google.
Interestingly, a third format is also in the pipeline. The Xiph. Nothing ever stays still in technology. Unlike other sites, we thoroughly review everything we recommend, using industry standard tests to evaluate products. We may get a commission if you buy via our price links. Tell us what you think — email the Editor. Home Opinion H. What are H. How do they work?
Which is better? Who is supporting what? Do I need to worry about format support? Trusted Reviews. Founded inTrusted Reviews exists to give our readers thorough, unbiased and independent advice on what to buy.
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