peppe
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![Post Post](./styles/etechdarkgreen/imageset/icon_topic_latest.gif) Codecs V4
At the heart of any media server is content; smoothly playing back video and audio files on demand. In order to ensure that media is played instantly, smoothly and accurately Hippotizer V4 stores all content internally in one of four Codecs.
These formats each have their own strengths: which one is best suited for a given application depends on your requirements.
No matter which Codec is chosen, encoding media into the system is easy; Hippotizer's Media Manager handles encoding content into the Hippotizer system. Every Hippotizer V4 ships pre-loaded with the required software to read many popular intermediate media including ProRes, MPEG-4, H.264/AVC, H.265, MPEG-2 and image sequences. Each V4 also comes complete with software to open Mac formatted drives to further simplify media ingest. The first step in the encode process is to choose a Hippotizer codec to encode to; there are four choices available in Media Manager’s Encoding settings.
When choosing which Codec to use, there are some important factors to consider such as media resolution, desired quality and overall system load. In order to store the media and play it back instantly, it must be compressed, the degree and effect of this compression depends on the Codec. The method of compression also has a strong influence on playback: each of our Codecs plays back smoothly under normal conditions however some are better than others at playing backwards or jumping around (scrubbing) for example. The load a clip places on the system to play is also critical, as this controls how much a Hippotizer can play at once smoothly. The Hippotizer system will render video more slowly (lower frames per second) as it becomes overloaded at what point this becomes noticeable depends on the content and application.
MPEG-2: The tried and true format of Hippotizer V3, MPEG-2 offers legacy support for Hippotizer V4 so existing V3 media libraries can be brought into V4. MPEG-2 continues to provide relatively low load playback while not supporting alpha transparency or resolutions greater than 1920 x 1152. MPEG-2 provides very good standard playback, but should not be used to play backwards or at high speed. The quality of MPEG-2 is generally good; however it can create noticeable artefacts especially in slow moving colour gradients. MPEG-2 is best used to playback legacy media libraries and where clips are smaller than HD without an alpha channel. FlexRes Quality:
First released in Beta in Hippotizer Version 3.3, FlexRes Quality was designed in-house by Green Hippo to provide the greater-then-HD support that MPEG-2 lacks, while supporting alpha transparency and wider colour spaces. FlexRes Quality allows the user to choose the encoding quality and colour sub-sampling. Setting the quality to 10 provides visually lossless encoding while quality 7 is similar to that of MPEG-2 in quality. Colour reproduction is also controllable, with 4:2:0, 4:2:2 and 4:4:4 modes available. FlexRes Quality supports any resolution or aspect ratio, provided it is an even number of pixels. Media playback at high speeds, during speed changes and backwards is also well supported by FlexRes Quality. The load that FlexRes Quality places on a Hippotizer system is difficult to quantify as it depends on the chosen quality, colour-space, resolution and the presence of the alpha channel. If the higher quality and colour settings are used especially, FlexRes Quality will place significant playback load on the Hippotizer system. FlexRes Quality is ideally suited for playing low numbers of very high quality clips, or supporting resolutions that will not work with the other FlexRes codecs. FlexRes Performance:
Using hardware acceleration, FlexRes Performance has a low CPU overhead, enabling multiple layers of 4K of media playback on even the smallest Hippotizer V4 systems. FlexRes Performance has several options to choose better quality or alpha channel support, if required. FlexRes Performance has the least system load of the FlexRes codecs, and supports any resolution of content as long as the size (height and width) is divisible by four. FlexRes Performance offers good visual quality with some visible encoding artefacts; the encoding quality can also be made better by selecting “improved quality” to use additional colour information. Enabling alpha support or improved quality makes FlexRes Performance slightly heavier in playback, though still less than a comparable clip in FlexRes Quality. FlexRes Lossless:
As the name implies, FlexRes Lossless provides lossless reproduction of the source video while supporting alpha transparency as well as any pixel sized media. This makes it an ideal choice where the playback of a single very high quality clip is critical. FlexRes Lossless is however extremely heavy to playback; using large amounts of disk space. FlexRes Lossless has been introduced in Beta format as of 4.0.2 Beta 2 of the Hippotizer V4 software.
Audio in Hippotizer V4:
Although video playback is the primary function of a Hippotizer, audio playback is also important and has been re-designed and improved for V4. Hippotizer V4 supports 16bit .Wav audio files in either stereo or 5.1 surround sound. Stereo output is handled on the on-board audio outputs on the V4 hardware; while 5.1 require an external audio card such as a Motu 828x. Summary With these options to choose from, it is best to compare all the codecs to each other for a specific use. If the codecs are graphed with the vertical axis showing their relative performance, with higher being more layers played at once. The quality and amount of compression depends on the content making comparison relative and not precise data points.
_________________ Peppe Tannemyr SSR Beacon DigiGobos® Sweden retailer of Hippo systems
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