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9th July 2018, 06:28 | #741 | Link | |
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9th July 2018, 15:47 | #742 | Link |
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AOM AV1 v1.0.0-82-gf77d93175
Built on July 09, 2018, GCC 7.3.0 Code:
https://aomedia.googlesource.com/aom Last edited by Barough; 9th July 2018 at 17:48. |
9th July 2018, 16:19 | #743 | Link | |
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9th July 2018, 17:50 | #744 | Link | |
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Last edited by Barough; 9th July 2018 at 18:05. |
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9th July 2018, 19:27 | #745 | Link | |
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It's a good sign of the health of AV1 that we are seeing a variety of different encoders, both open-source and proprietary, being worked on. VPx never had enough interest to get that effort. Competition drives tons of implementation innovations in encoding. That's why we're still seeing significant improvements in MPEG-2 after all these years. |
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10th July 2018, 07:21 | #748 | Link |
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I think I have read this statement sometime ago and may have asked a similar question before. What are the use case of MPEG-2 today? From high end bitrate to low end I cant think of a single use case where it would be valuable.
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10th July 2018, 08:29 | #749 | Link | |
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- Terrestrial broadcast in the US using ATSC is 100% MPEG-2 for now. - Legacy cable / satellite networks with tons of existing decoders / professional IRDs in the field - Legacy broadcast contribution, especially at high bitrates for backup. - Legacy cable VOD (still pushing 15 Mbps 1080i MPEG-2 in most cases) - Broadcast playout - quite heavily using 50 Mbps XDCAM HD422, sometimes even lower quality. TBH, for anything new that's for distribution, yeah you wouldn't use MPEG-2 most likely. However, legacy stuff has a habit of staying around forever. Plenty of current premium satellite TV networks use MPEG-2 as their house format because surrounding standards like XDCAM HD422 in MXF have robust support for in-band metadata like captioning, timecode, AFD, etc, and also have broad support from playout server vendors, NLE / post production tools, and pro transcoder tools. The other benefit is that MPEG-2 is quite lightweight to decode these days, so a video server can be dense and cost effective and still perform perfect frame accurate seeking and smooth playback, saving CPU cycles for graphics etc. Quality is definitely "good enough" (especially considering transmission encoding typically being 6-12 Mbps real-time encoded CBR H.264 with small GOPs and tight buffers). More modern alternatives like J2K (a-la AS-02 style MXF) and AVC Intra do have benefits in certain cases, especially where very high quality is desired, but they typically come with additional cost in terms of processing power, software licensing, and storage capacity. Higher quality formats tend to live in acquisition and post production. When you deliver to playout, 1080i XDCAM HD422 is probably the most common standard - at least in the US. The broadcast industry as a whole tends to cling to the melting icebergs of trust for as long as possible, and TBH this is for good reason. Any change that introduces potential risk is an extremely tough sell when you have 4 or 5 nines of uptime required in your SLA. It only takes a few minutes of downtime per year to start feeling the pain. I've heard of some improvements in MPEG-2 especially for H.264 -> MPEG-2 transcoders to glue new channels into legacy infrastructure, but TBH this was years ago. I haven't heard of anything major recently. Ben, care to share? Last edited by Blue_MiSfit; 10th July 2018 at 08:35. |
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10th July 2018, 21:49 | #750 | Link | |
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Granted statmuxed MPEG-2 is kind of a special case, except that it probably accounts for the majority of MPEG-2 eyeball hours these days. (for those blissfully ignorant of channel-based broadcast world, statmuxing is when multiple video streams are encoded in parallel to fit within a given amount of total bandwidth. Basically inter-stream VBR). |
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12th July 2018, 20:05 | #753 | Link |
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Official? Well, aomenc is already available as codec for ffmpeg; and HandBrake uses an ffmpeg core, you just need to build a recent version or hope for one to be released.
Whether it is "good" ... your demands, you opinion. |
12th July 2018, 20:06 | #754 | Link | |
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I wouldn't expect to have everyone using one "official" encoder like libvpx with AV1 if AV1 gets significantly broad market adoption. VPx had mainly a very small number of very large companies using it. |
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13th July 2018, 03:11 | #755 | Link | |
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From encoding strategy or algorithm point of view, are these AV1 encoders developed by Mozilla or EVE have any difference compare to the one from AOM? Or just mainly encoding speed up? Last edited by olduser217; 13th July 2018 at 03:23. |
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13th July 2018, 19:16 | #757 | Link |
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Certainly not for large scale content publishing.
Given historical encoder development, I wouldn't expect AV1 encoders to be able to practically compete with HEVC encoders for large commercial mission-critical live/VOD applications before Q4 2019. There's a long path from "look, I can encode a little clip in two days that'll play in this pre-release web browser" to "this is good enough to replace the stuff I bet my business on already." And 1080p and UHD are things, and the current AV1 are too slow to do enough encoding at those resolutions for tuning, and optimal tuning can be quite different at higher resolutions, particularly 2160p. So no one really even knows how suitable AV1 is as a technology, let alone how applicable current encoders are for it. Beyond quality @ perf, there's tons of integration effort along many end-to-end pipelines. And some of those pipelines will require a decent quality 2160p60 low latency live encoder. In theory it's obvious how it works, but in practice SO many little things will and do go wrong. Even with mature codecs, you try to raise the reference frame count of a low bitrate stream (still staying under profile @ level minimum), and you realize that some mobile chipset's DRM implementation requires a boot-time memory carveout of max ref frames * max frame size. So if you use 6 refs at 320x240, and your max frame size is 1920x1080, you still need to carve out 6 1920x1080 frames. So many little implementation details like that need to get discovered and ironed out with every new codec. One advantage of AV1 is that supporting chipsets will all be newer, so the backwards compatibility won't be as fraught. But in many cases, fraught backwards compatibility is vastly better than none at all. That's why tons of broadcast/cable is still MPEG-2. |
19th July 2018, 21:08 | #760 | Link |
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Both have methods to improve quality, as well. EVE gives a large improvement over libvpx quality via a number of methods. rav1e is not nearly as far along, but does already have psy optimization, unlike libaom. You can try it out with the --tune psychovisual flag if you like.
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