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3rd April 2018, 08:35 | #581 | Link |
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libaom would need to have an API to parse string parameters like that, I do not know if that is the case.
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LAV Filters - open source ffmpeg based media splitter and decoders |
5th April 2018, 07:11 | #586 | Link | |
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webm 1 (vp8/vorbis) webm 2 (vp9/opus) webm 3 (av1/opus) when all browsers and players get support hehe you should be able to just play it fine and the current av1 encoder is so slow that even vp9 with row-mt=1 runs circles around it
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Woah! Ninja?! http://nwgat.ninja/ (AV1 Overview) "Not available in your region" has now been redefined as "Go Pirate, you filthy scum" Nwgat Last edited by wiak; 5th April 2018 at 07:17. |
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5th April 2018, 07:40 | #587 | Link |
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The storage format for AV1-in-Matroska is the same as the one for AV1-in-WebM, it's even the same for AV1-in-IVF. No CodecPrivate, each Block starts with a TD OBU and contains all following OBUs up to but excluding the following TD OBU. Dead simple.
And yes, they're still changing the bitstream. Just yesterday an additional bit ("still_picture") was added to the sequence header OBU, and five days ago the profile indicator was changed from two to three bits. Luckily reading AV1 from IVF or WebM doesn't require parsing the sequence header OBU (and therefore mkvmerge already supports those two source containers for AV1), but it is required for reading raw OBU streams. I do have the code for that already, but I won't include it as long as the bitstream is in that much flux.
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Latest MKVToolNix is v83.0 If I ever ask you to upload something, please use my file server. Last edited by Mosu; 5th April 2018 at 07:42. |
5th April 2018, 08:10 | #588 | Link |
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I talked with a few people involved in AV1 the other day and they said that AV1 in WebM/MKV is not actually finally specified yet. For example, AV1 in ISOMBFF (MP4) is still under discussion, among other things about the bitstream format allowed in the container, since AV1 has two of those (Annex B and "normal"), and if both would be allowed you would need CodecPrivate to tell the difference. For consistencies sake, I would hope that WebM/MKV would follow the same logic that MP4 takes, so we don't have to deal with yet another difference.
I definitely didn't find a AV1-in-WebM/MKV spec written down anywhere, for that matter.
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LAV Filters - open source ffmpeg based media splitter and decoders Last edited by nevcairiel; 5th April 2018 at 08:14. |
5th April 2018, 08:21 | #589 | Link |
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I've read both the current AV1-in-MP4 spec draft as well as Annex B storage method. What I don't quite get is why there's the Annex B format when the OBUs themselves already contain a length field, albeit an optional one (the "obu_size" syntax element with "obu_has_size_field" set to 1). Wouldn't it have sufficed to make that mandatory in certain situations?
I definitely agree that storage-in-WebM/Matroska and storage-in-MP4 should work the same way as much as possible.
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5th April 2018, 08:50 | #590 | Link |
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Yeah I don't understand that part either. One reasoning I have stumbled upon seems to be that RTP transport tries to optimize transmission for every single byte, so they don't have the size field in the OBU, and instead of wanting to re-write the OBU header to add it on the RTP depacketizers side, they prefer to just add the Annex B size headers.
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5th April 2018, 10:36 | #591 | Link | |
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5th April 2018, 10:40 | #592 | Link | |
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5th April 2018, 10:44 | #593 | Link |
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The spec is indeed not finished yet, people all fell victim to a PR marketing push for the upcoming tradeshow. But presumably its on a deadline to actually get finished soon.
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LAV Filters - open source ffmpeg based media splitter and decoders |
5th April 2018, 11:07 | #594 | Link |
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It is probable that HW manufacturers wanted something to work with as well, since most of the large tools need to be implemented at one point or another in silicon which takes time. A couple minor issues in the bitstream can be fixed later before tape-out.
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5th April 2018, 11:10 | #595 | Link |
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You don't need to post a big PR thing that its finished (when its not) for the HW people to start working on it. The big HW companies are involved in the development of the codec anyway. Its pure marketing.
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5th April 2018, 12:58 | #596 | Link | |
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5th April 2018, 14:17 | #597 | Link | |
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5th April 2018, 14:25 | #598 | Link |
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vp9 with row-mt improved it a hell of alot
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Woah! Ninja?! http://nwgat.ninja/ (AV1 Overview) "Not available in your region" has now been redefined as "Go Pirate, you filthy scum" Nwgat |
5th April 2018, 15:31 | #600 | Link | |
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Woah! Ninja?! http://nwgat.ninja/ (AV1 Overview) "Not available in your region" has now been redefined as "Go Pirate, you filthy scum" Nwgat |
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