Re: [rtcweb] H261/MPEG-1 video quality
Toerless Eckert <eckert@cisco.com> Sun, 17 November 2013 17:58 UTC
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Date: Sun, 17 Nov 2013 09:56:48 -0800
From: Toerless Eckert <eckert@cisco.com>
To: Maik Merten <maikmerten@googlemail.com>
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References: <5284AB73.5030505@googlemail.com> <5285209D.7020407@googlemail.com> <CAGgHUiSROwRznKZWD4kjn8Vu7SrUVwOnHN1EJ-PTgR=WQmcxAQ@mail.gmail.com> <CAOJ7v-2najyMhcVNC8r0Sg+8xgkgDwasBSz476zA0BEpi2X5Pg@mail.gmail.com> <528559E4.3020903@nostrum.com> <5286272B.5000005@bbs.darktech.org> <CAOJ7v-3AT-5BHZAp2hvqm3Th20dk8Ec3orrj-voFMBwZroPdLA@mail.gmail.com> <DUB127-W49A2377699D81E3A1EA912E0FB0@phx.gbl> <CAOJ7v-27XiBGFT8=i=8ZyWYPP4UE64Jo41Pe_i1GAAUWfhDBuA@mail.gmail.com> <52877178.6040002@googlemail.com>
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Cc: rtcweb@ietf.org
Subject: Re: [rtcweb] H261/MPEG-1 video quality
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On Sat, Nov 16, 2013 at 02:22:00PM +0100, Maik Merten wrote: > A major reason IMO why H.261 performs so badly (apart from the old > format design) is that nobody seems to have cared to transfer new > technology for determining smart encoding choices to that old format (it > just makes little commercial sense to strap rockets onto a pig if a > newer format such as H.263 or H.264 is available). It appears that > encoders for H.261 are mostly "1990ies" regarding encoding technology. > From today's point of view such encoders are blazingly fast, but better > quality could be achieved with encoders that spend some computation on > making smarter encoding choices. Right. I think the logics of the market space would make a choice of h261 as MTI just a big desaster and fruitless exercise in retro-engineering. - You start with legacy software, then it breaks under a lot more/different use than what it was written for in the 90th and you have to invest cycles fixing it. - You wonder whether you should still optimize it, but ohh, wait, lets check IPR on any possible optimization, oh wait, if i need to start checking IPR, why the heck did i use this legacy codec. - You try to figure how to make chips work whose native h261 support if at all still existing still works. YOu wonder if/how the next generation of chips could do better on h261. Toerless > Maik > > > Am 16.11.2013 03:18, schrieb Justin Uberti: > >Thanks. Performance at 256 kbps is clearly unacceptable, 1933 kbps is > >pretty decent. Would be great to see a 512 kbps and 1024 kbps version to > >understand where things go from bad to good. > > > > > >On Fri, Nov 15, 2013 at 3:42 PM, Hervé W. <h_o_w_@hotmail.com > ><mailto:h_o_w_@hotmail.com>> wrote: > > > > <http://ge.tt/2bp1Zrz><http://ge.tt/2bp1Zrz><http://ge.tt/2bp1Zrz>http://ge.tt/2bp1Zrz > > > > options used: > > mencoder.exe -ovc lavc -lavcopts vcodec=h261:vbitrate=256 -o > > irene-256k.h261.avi sign_irene_cif.y4m > > > > mencoder.exe -ovc lavc -lavcopts > > vcodec=h261:vbitrate=256:last_pred=3:predia=2:dia=2:precmp=2:cmp=2:subcmp=2:preme=2:mbd=0 > > -o irene-256k.h261.miscoptions.avi sign_irene_cif.y4m > > > > mencoder.exe -ovc lavc -lavcopts > > vcodec=h261:vbitrate=15999:last_pred=3:predia=2:dia=2:precmp=2:cmp=2:subcmp=2:preme=2:mbd=0 > > -o irene-highbitrate.h261.avi sign_irene_cif.y4m > > > > You can probably derive ffmpeg/avconv options from those. > > > > Notes > > > > * There's a ticket open about h261 > > <https://trac.ffmpeg.org/ticket/3143>https://trac.ffmpeg.org/ticket/3143 > > * 15999 kbps was not the bitrate irene-highbitrate ended up using; > > that was more like 1933 kbps > > * My untrained eye did not see any difference between > > irene-256k.h261.avi and irene-256k.h261.miscoptions.avi but > > maybe most of those options are (rightly) ignored for h261. > > > > > > - Hervé > > > > ------------------------------------------------------------------------ > > From: juberti@google.com <mailto:juberti@google.com> > > Date: Fri, 15 Nov 2013 14:00:50 -0800 > > To: cowwoc@bbs.darktech.org <mailto:cowwoc@bbs.darktech.org> > > CC: rtcweb@ietf.org <mailto:rtcweb@ietf.org> > > Subject: Re: [rtcweb] H261/MPEG-1 video quality (was: I'd love it if > > patents evaporated) > > > > > > From what I understand, the clip from this thread was encoded using > > MPEG-1, not H.261. Aside from > > http://www-mobile.ecs.soton.ac.uk/peter/h261/, I don't think we have > > seen any samples of actual H.261 output that give a good indication > > of its suitability. > > > > > > On Fri, Nov 15, 2013 at 5:52 AM, cowwoc <cowwoc@bbs.darktech.org > > <mailto:cowwoc@bbs.darktech.org>> wrote: > > > > > > Excellent work Adam. I can't speak for others, but at 254 kbps > > (corrected figure from your follow-up post) H.261 is definitely > > "good enough" and better than an audio-only connection. > > > > Gili > > > > > > On 14/11/2013 6:16 PM, Adam Roach wrote: > > > > I sent a reply to this earlier, but just now realized that > > it went only to Justin, not to the list. > > > > > > On 11/14/13 13:59, Justin Uberti wrote: > > > > Thanks, this is interesting. Is the ffmpeg 261 encoder > > limited to CIF/QCIF, or can you specify arbitrary sizes? > > > > > > It looks like the ffmpeg mpeg-1 coder works for arbitrary > > sizes. I'm not sure what the difference between mpeg-1 and > > H.261 are, though, so we could be talking apples and oranges > > (or at least apples and pears) here. I'll note that mpeg-1 > > came out in 1991, which is a good 22 years in the past. I'm > > not drawing IPR conclusions for you, but invite you to > > ponder the implications yourself. > > > > Following Maik's lead with the mpeg-1 js decoder, I put this > > together: > > > > https://dl.dropboxusercontent.com/u/53717247/mpg/maven.html > > > > ...with this commandline: > > > > ffmpeg -i maven.mp4 -f mpeg1video -flags qprd -mbd rd > > -cmp rd -subcmp rd -mbcmp rd -precmp rd -trellis 2 -g 100 > > -vb 256k maven.mpg > > > > I don't really understand most of those options (I just > > cribbed them from Maik's example) or whether any of them > > would introduce more latency than is reasonable for a > > real-time conversation, but I will observe: > > > > 1. The encoder claims that it was performing on the order > > of 90 - 100 fps on my (admittedly modern) system; > > 2. The resolution is 640x360 (somewhat larger than DCIF); > > 3. The video is not, to my eye, unusable (draw your own > > conclusions, as it's clearly not as nice as modern codecs); > > 4. At 74 seconds and 4.7 MBytes (i.e., 37.6 Mbits), this > > encoding works out to 508 kbits/second total. > > > > > > > > Source video here, and NASA is acknowledged as the source of > > the material contained therein: > > http://www.youtube.com/watch?v=ijAO0FFExx0 > > > > /a > > > > > > > > _______________________________________________ > > rtcweb mailing list > > rtcweb@ietf.org <mailto:rtcweb@ietf.org> > > https://www.ietf.org/mailman/listinfo/rtcweb > > > > > > > > _______________________________________________ > > rtcweb mailing list > > rtcweb@ietf.org <mailto:rtcweb@ietf.org> > > https://www.ietf.org/mailman/listinfo/rtcweb > > > > > > > > _______________________________________________ rtcweb mailing list > > rtcweb@ietf.org <mailto:rtcweb@ietf.org> > > https://www.ietf.org/mailman/listinfo/rtcweb > > > > > > > > > >_______________________________________________ > >rtcweb mailing list > >rtcweb@ietf.org > >https://www.ietf.org/mailman/listinfo/rtcweb > > > > _______________________________________________ > rtcweb mailing list > rtcweb@ietf.org > https://www.ietf.org/mailman/listinfo/rtcweb -- --- Toerless Eckert, eckert@cisco.com Cisco NSSTG Systems & Technology Architecture SDN: Let me play with the network, mommy!
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Leon Geyser
- [rtcweb] H261/MPEG-1 video quality (was: I'd love… Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Gili
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Justin Uberti
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Gili
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Adam Roach
- Re: [rtcweb] H261/MPEG-1 video quality Adam Roach
- Re: [rtcweb] H261/MPEG-1 video quality Stephan Wenger
- Re: [rtcweb] H261/MPEG-1 video quality Leon Geyser
- Re: [rtcweb] H261/MPEG-1 video quality Monty Montgomery
- Re: [rtcweb] H261/MPEG-1 video quality Leon Geyser
- Re: [rtcweb] H261/MPEG-1 video quality Magnus Westerlund
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality cowwoc
- Re: [rtcweb] H261/MPEG-1 video quality cowwoc
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … cowwoc
- Re: [rtcweb] H261/MPEG-1 video quality Harald Alvestrand
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality cowwoc
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Justin Uberti
- Re: [rtcweb] H261/MPEG-1 video quality Adam Roach
- Re: [rtcweb] H261/MPEG-1 video quality (was: I'd … Justin Uberti
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Stephan Wenger
- Re: [rtcweb] H261/MPEG-1 video quality Gunnar Hellstrom
- Re: [rtcweb] H261/MPEG-1 video quality Randell Jesup
- Re: [rtcweb] H261/MPEG-1 video quality Adam Roach
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- Re: [rtcweb] H261/MPEG-1 video quality Stephan Wenger
- Re: [rtcweb] H261/MPEG-1 video quality Toerless Eckert
- Re: [rtcweb] H261/MPEG-1 video quality Toerless Eckert
- Re: [rtcweb] H261/MPEG-1 video quality Maik Merten
- [rtcweb] Trellis IPR status? (Re: H261/MPEG-1 vid… Harald Alvestrand
- Re: [rtcweb] Trellis IPR status? (Re: H261/MPEG-1… Maik Merten
- Re: [rtcweb] Trellis IPR status? (Re: H261/MPEG-1… Harald Alvestrand
- Re: [rtcweb] Trellis IPR status? (Re: H261/MPEG-1… Maik Merten