The goal was to understand the qualitative and performance trade-offs associated with the various presets. With MainConcept, I tested P/Q values 1 (lowest quality, fastest encode), 15 (the default), 22, 27, and 30 (highest quality/slowest encode) while keeping all other parameters identical. After running the tests, I compared quality using the Moscow State University Video Quality Measurement Tool’s Video Quality Metric (VQM) rating to assess output quality, and verifying the findings with subjective comparisons. With all encodes, I verified that the encoder met the target rate, which proved much more of an issue with x.265 than with TotalCode. I produced the x265 files via command line using version 1.4.0 of the x265 video encoder. I encoded the MainConcept files using version 3.2.0 (build 17871) of MainConcept’s TotalCode Studio. I tested each codec using five different standardized presets that I’ll identify below.
#Permute high quality vs. keep quality 1080p#
I tested at 1080p resolution encoding to the Main (rather than Main10) HEVC profile at 2Mbps per second, encoding to 1-pass CBR with a key frame interval of 60 frames. The distinct content obviously stressed the codecs in different ways, while the short duration enabled me to run hundreds of discrete encodes.
#Permute high quality vs. keep quality series#
How I Testedįor this series of tests, I used seven 5-second files with varying content, ranging from a low-motion, low-detail talking head video to a high-detail, high-motion shot of a Food City parking lot with lots of trees and bush, shot from a rising lift on a windy day. Before jumping into the results, let’s discuss how and what I tested. When using either codec, the most important issue is determining which preset is right for your encoding operation, so I’ll address this topic first. With the x265 codec, the Medium preset is the default with MainConcept, 15 is the default. Rather than using a preset, MainConcept uses a P/Q selection, which ranges from 1 (Fastest Encode/Poorest Quality) to 30 (Slowest Encode/Best Quality). Both encoders provide access to x265 tuning alternatives, which I did not explore in this article. Sorenson Squeeze, which also uses the x265 codec, lets you choose a preset and access all other encoding parameters within the actual encoding interface. With Vantage, you can choose a preset and customize your HEVC encode even further by inserting command-line arguments in the field below the preset. Choosing an x265 preset in Telestream Vantage This is shown in Figure 2, the preset selection screen from Telestream Vantage, which uses the x265 codec.įig 2. To simplify operation for their users, both MainConcept and the developers of x265 (led by Multicore and sponsored by Telestream and Sorenson) create presets that represent relevant trade-offs between encoding time and output quality. Most advanced codecs include dozens of configuration options that can lead to thousands, if not millions, of unique configuration permutations. None of the rules regarding these items have changed in theory, so you can apply them just as you always have, though obviously you’ll be using a different data rate than you would for H.264. Where H.264 has greater precision than MPEG-2, especially in the Transform and Motion Estimation Blocks, HEVC has greater precision than H.264, though some of this is “under the hood” and not configurable with either codec.īecause of these fundamental similarities, much of your decision making when encoding with HEVC will relate to familiar configuration items: I- and B-frame interval, data rate selection, and bitrate control technique (VBR, CBR). This is shown in Figure 1, which is from the Elemental Technologies White Paper “HEVC Demystified: A Primer on the H.265 Video Codec.” As you can see, the general concepts are similar, as are the frame types and various other elements.
So addressing these two HEVC codecs delivers the best bang for our editorial buck.įortunately, H.264 and HEVC are very similar from an encoding perspective, just as MPEG-2 and H.264 are.
Why these codecs? Because while there are some encoding vendors who will create and deploy their own HEVC codecs, most encoding vendors will incorporate one of these codecs, just like most encoding tools have incorporated the MainConcept H.264 codec and/or x264. No worries, we’re here to help with this guide to encoding to HEVC using the MainConcept and x265 HEVC codecs. If you haven’t already, sometime in 2015 you’ll have to encode your files to HEVC format for the first time.
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