Re: [rtcweb] H261/MPEG-1 video quality

Leon Geyser <lgeyser@gmail.com> Fri, 15 November 2013 05:57 UTC

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Date: Fri, 15 Nov 2013 07:57:32 +0200
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From: Leon Geyser <lgeyser@gmail.com>
To: "rtcweb@ietf.org" <rtcweb@ietf.org>
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Subject: Re: [rtcweb] H261/MPEG-1 video quality
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Hi Monty,

I do like Theora; it compares well against MPEG-4 Part 2:ASP, but won't the
reasons why some people don't want to implement VP8 be the same for Theora?


On 15 November 2013 07:39, Monty Montgomery <xiphmont@gmail.com> wrote:

> Stephan just implied strongly they haven't, despite the 20 years.
>
> And, BTW, I was serious when I mentioned Theora earlier as well.
>
> Monty
>
> On Fri, Nov 15, 2013 at 12:33 AM, Leon Geyser <lgeyser@gmail.com> wrote:
> > Hi everyone,
> > Maybe MPEG-1 Part 2 would be a better alternative to H.261. How can we
> > figure out if all the patents have expired for MPEG-1 Part 2?
> >
> >
> > On 15 November 2013 03:37, Stephan Wenger <stewe@stewe.org> wrote:
> >>
> >> Folks,
> >> Please don’t consider H.261 and MPEG-1 part 2 as being in the same
> league
> >> in terms of coding efficiency or network friendliness.  They clearly are
> >> not.
> >> H.261 is what many call the first generation video coding standard.
> >> MPEG-1 (and MPEG-2) are second generation.
> >> MPEG-1 has half-pel motion compensation.  H.261 has not.
> >> MPEG-1 has B frames.  H.261 has not.
> >> MPEG-1 has (arbitrary sized) slices that can be used for MTU size
> matching
> >> (although they are not commonly used for that purpose).  H.261 has not.
> >> Instead, H.261 has the Group Of Block picture segmentation mechanism,
> that
> >> is clearly more optimized for parallel processing than for MTU size
> >> matching.
> >> MPEG-1 allows for significantly larger motion vectors (necessitated by B
> >> frames and the resulting longer prediction interval, but can be used
> even in
> >> P frame only coding).
> >> MPEG-1 has arbitrary picture sizes.  H.261 allows QCIF, CIF, and 4CIF
> (in
> >> “still image” mode, designed for low frame rate application; could run
> at
> >> high frame rate though).
> >> H.261 was ratified (in its first version) in 1988, and in the for all
> >> practical purposes final version in 1989.  Most people believe that all
> >> related patents have expired.
> >> MPEG-1 was ratified in late 1992.  Its “bug fix” successor MPEG-2 (which
> >> adds interlace support) was ratified less than a year later.  There are
> at
> >> least two major disputes going on today regarding technology allegedly
> >> infringed by a compliant implementation of MPEG-2.  Based on my
> technical
> >> understanding, one of these technologies is not in any way related to
> >> interlaced.
> >> Draw your own conclusions.
> >> Regards,
> >> Stephan
> >>
> >>
> >>
> >>
> >> From: Adam Roach <adam@nostrum.com>
> >> Date: Thursday, 14 November, 2013 at 15:22
> >> To: "rtcweb@ietf.org" <rtcweb@ietf.org>
> >> Subject: Re: [rtcweb] H261/MPEG-1 video quality
> >>
> >> On 11/14/13 17:16, Adam Roach wrote:
> >>
> >> At 74 seconds and 4.7 MBytes (i.e., 37.6 Mbits), this encoding works out
> >> to 508 kbits/second total.
> >>
> >>
> >> Whoops, I messed up my math. It's 148 seconds long, not 74 (Quicktime
> >> seems to divide it by two for some reason, although the javascript
> decode
> >> does the right thing). This works out to 254 kbps.
> >>
> >> /a
> >>
> >> _______________________________________________
> >> rtcweb mailing list
> >> rtcweb@ietf.org
> >> https://www.ietf.org/mailman/listinfo/rtcweb
> >>
> >
> >
> > _______________________________________________
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> > rtcweb@ietf.org
> > https://www.ietf.org/mailman/listinfo/rtcweb
> >
>