[pipo234]

+1 Indeed.

Compared to other standards in streaming media, I'd say that AOMedia has found adoption a lot quicker. h265 (HEVC) was all but DoA until years after it's introduction Apple finally decided to embrace it. It is still by no means ubiquitous, mostly due to patent licensing, which significantly drives up the price of hardware in single digit dollars price range.

Anecdotally, consider that Apple's HTTP Live Streaming protocol (till version 6) relied on MPEG2TS, even though Apple lay the groundwork for ISO/IEC 14496-12 Base Media File Format aka MP4. The reason was that chips in the initial Iphones had only support for h264 using mpeg2 transport streams, and even mp4 -> mp2 transmuxing was considered too resource intensive.

[bscphil]

> h265 (HEVC) was all but DoA until years after it's introduction Apple finally decided to embrace it

No? You're talking in terms of PC / phone hardware support only. HEVC was first released June 7, 2013. The UHD Blu-ray standard was released less than 3 years later on February 14, 2016 - and it was obvious to everyone in the intervening years that UHD Blu-ray would use HEVC because it needed support for 4k and HDR, both of which HEVC was specifically designed to be compatible with. (Wikipedia says licensing for UHD Blu-ray on the basis of a released spec began in mid 2015.)

[dylan604]

>Anecdotally, consider that Apple's HTTP Live Streaming protocol (till version 6) relied on MPEG2TS

This sounds like you might be confusing that MPEG2TS might have something to do with the video encoding instead of it solely being the way the video/audio elementary streams are wrapped together into a single contained format. The transport stream was designed specifically for an unreliable streaming type of delivery vs a steady consistent type of source like reading from a dis[c|k]. There is nothing wrong with using a TS stream for HLS that makes it inferior.

[repelsteeltje]

> There is nothing wrong with using a TS stream for HLS that makes it inferior.

Not wrong, but a bit surprising. As you mention, transport streams are designed to operate over unreliable connections (like satellite or terrestrial transmission). Reliability is not an issue with with HTTP or TCP.

Other than being archaic, some disadvantages are that TS has somewhat more overhead than (f)MP4 and poor ergonomics for random access / on the fly repackaging caused by continuity counter, padding, PAT/PMT resubmission timing, PCR clock.

If it were up to me to design a streaming protocol like DASH, HLS, Flash, or SmoothStreaming I'd instantly choose mp4 (or plain elementary streams). I wouldn't even consider TS or PS unless some spec forced me to.

[dylan604]

>Reliability is not an issue with with HTTP or TCP.

We seem to be confusing what reliable means here. Yes, HTTP/TCP can reliably transmit data in the fact that if packets are missed they will be resent so that you can be assured that the data will eventually be delivered. However, that doesn't do well for real time streaming of data that is necessary to be received in order. That's why UDP was made.

>If it were up to me to design a streaming protocol like DASH, HLS, Flash, or SmoothStreaming I'd instantly choose mp4 (or plain elementary streams). I wouldn't even consider TS or PS unless some spec forced me to.

Well, it's a good thing we didn't have to wait for you to come around and design a streaming protocol and we've been able to use it for the past ~20 years with the technology that was available at the time. Perfect is the enemy of progress.

[repelsteeltje]

> However, that doesn't do well for real time streaming of data that is necessary to be received in order. That's why UDP was made.

Sure, but UDP was not part of the HLS draft https://www.rfc-editor.org/rfc/rfc8216

> Perfect is the enemy of progress.

Touché ;-)

What I meant to point out as odd about Roger Panthos and co.'s decision to build HLS on top of Transport Stream containers is that Apple had already laid the foundation for MP4 with QuickTime.

Since HTTP live streaming was never about anything but HTTP, container capabilities like auto-synchronization offered by mpeg2TS were moot. It would therefore seem logical for Apple to build HLS upon what they already had with QuickTime + iso2 fragments. That was more or less the route Adobe/Macromedia had taken with Flash streaming.

Yet, the choose mpeg2TS (initially only muxing AAC and h264). The reason, historically seems to have been driven primarily by the capabilities of the iphone hardware which supported this out of the box! Separate transport streams for audio and video, WebVTT, elementary stream audio were added much later, and fragmented MP4 was introduced only once HEVC was bolted on.

I'm all for favouring what exists over what's perfect; it's just odd that Apple choose to (initially, at least) regress to 90s technology while rest of world had already adopted superior container.

[throw0101c]

> Compared to other standards in streaming media, I'd say that AOMedia has found adoption a lot quicker. h265 (HEVC) was all but DoA until years after it's introduction Apple finally decided to embrace it.

Well, there's now H.266 as well:

* https://en.wikipedia.org/wiki/Versatile_Video_Coding

[ZeroGravitas]

MPEG realeased three codecs that year, as well as VVC there was EVC and LCEVC:

https://en.wikipedia.org/wiki/Essential_Video_Coding

https://en.wikipedia.org/wiki/LCEVC

Note EVC and LCEVC are two entirely different approaches to codecs despite the similar names.

[7speter]

Was it all but dead because people thought h264 was good enough, until 2.5 and 4k became more prominent in media consumption? It seems really useful if youre doing encoding at resolutions than 1080p, and it makes me less regretful that I have a bunch of recent hardware that didn’t get av1 hardware support :)

[pipo234]

> Was it all but dead because people thought h264 was good enough, until 2.5 and 4k became more prominent in media consumption?

(Lack of) a compelling use case certainly played a role. Sure, reducing bandwidth is in itself a noble (and potentially profitable) goal but why fix it if it ain't broken? Ie.: the h264 infrastructure for HD was already there, working fine.

Another factor was that HEVC was full of new patents and the patent pool licensing costs hadn't yet settled.

[londons_explore]

> even mp4 -> mp2 transmuxing was considered too resource intensive.

Really? Muxing generally doesn't require one to decode the actual data - merely shuffle around blocks of data with memcpy() so should be really cheap.

[repelsteeltje]

memcpy is ±99%. The 1% involves bit shifting (nal unit reshuffling, avc3/avc1 fixups).

So indeed, repackaging mp4 <-> mp2 containers is pretty trivial. Nevertheless, Apple initially choose mpeg2TS because it conveniently allowed them to shove the reassembled media segments straight into the dedicated AV chip.