Re: [rtcweb] H261/MPEG-1 video quality
Maik Merten <maikmerten@googlemail.com> Thu, 14 November 2013 19:54 UTC
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Date: Thu, 14 Nov 2013 20:54:15 +0100
From: Maik Merten <maikmerten@googlemail.com>
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Subject: Re: [rtcweb] H261/MPEG-1 video quality
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I included the JavaScript MPEG decoder so that people can have a quick look. I don't propose that videos should be decoded in JavaScript for WebRTC. If anything this merely demonstrates that old codecs have low processing requirements (duh!). Maik Am 14.11.2013 20:48, schrieb Gili: > > Just a reminder: Native applications don't necessarily have access to > Javascript (they're running outside of a browser) so a Javascript-based > solution sounds problematic to me. Everything we need should be > accessible from WebRTC's Native API. If that happens to include a > Javascript engine under the hood, so be it, but I just want to make sure > this is understood. > > Thanks, > Gili > > On 14/11/2013 2:35 PM, Leon Geyser wrote: >> >>This includes a completely JavaScript-based MPEG-1 player for those >> that don't happen to have a fitting decoder installed >>(also, yay, >> JavaScript is fast enough now for simple video decoders!). I recreated >> the encoded files to ensure there are no >>b-frames and documented the >> encoder settings accordingly. >> Thanks for sharing. Looks better than what I expected. >> >> On 14 November 2013 21:12, Maik Merten <maikmerten@googlemail.com >> <mailto:maikmerten@googlemail.com>> wrote: >> >> Hello again, >> >> to allow for having a quick look at some test sequences I put >> together a very very sloppy overview page at >> >> https://dl.dropboxusercontent.com/u/14053306/mpeg1/index.html >> >> >> This includes a completely JavaScript-based MPEG-1 player for >> those that don't happen to have a fitting decoder installed (also, >> yay, JavaScript is fast enough now for simple video decoders!). I >> recreated the encoded files to ensure there are no b-frames and >> documented the encoder settings accordingly. >> >> Best regards, >> >> Maik >> >> >> Am 14.11.2013 11:52, schrieb Maik Merten: >> >> Hello all, >> >> in >> http://www.ietf.org/mail-archive/web/rtcweb/current/msg09721.html >> a >> sample of H.261 video was provided, connected to a (rhetorical?) >> question if this provided quality would be acceptable for >> users. Clearly >> that provided sample is of very low and unacceptable quality. >> >> Just for comparison, here are two CIF samples at roughly 256k >> created by >> a somewhat modern encoder (ffmpeg with rate/distortion >> optimization): >> >> >> https://dl.dropboxusercontent.com/u/14053306/mpeg1/irene-256k.mpg >> >> https://dl.dropboxusercontent.com/u/14053306/mpeg1/mad900-256k.mpg >> >> >> (encoded as MPEG-1 video, as the "h261" encoder in ffmpeg >> crashes when >> using rate/distortion optimization. I understand MPEG-1 if >> used without >> b-frames is similar to H.261 in coding efficiency, but mostly >> adds more >> flexibility regarding frame sizes. >> >> ffmpeg -i sign_irene_cif.y4m -vcodec mpeg1video -mbd rd >> -trellis 2 -cmp >> 2 -subcmp 2 -g 100 -vb 256k irene-256k.mpg ) >> >> Even without formal testing it is obvious that H.261 and/or >> MPEG-1 video >> is clearly outperformed in terms of coding efficiency by H.264 >> and VP8. >> However, personally, speaking as an end-user, I would very >> much prefer >> this video quality over audio-only calls (in cases where >> transcoding is >> not available), as the video produced still carries useful >> information. >> Also H.261/MPEG-1 is blazingly fast, can be dealt with in >> software, and >> is not exceedingly difficult to implement. >> >> Of course a MTI codec with higher coding performance is much >> preferable. >> However, if no such high-performance codec with licensing >> terms that are >> acceptable for all communities can be agreed on I think it may >> be wise >> to seriously evaluate the option of implementing an outdated >> codec for >> the sake of interoperability. In practice, most calls will >> negotiate to >> H.264 and VP8 anyways, but sporadic negotiation failures that are >> difficult to account for by the user are still to be expected >> if no MTI >> codec is defined at all. >> >> >> >> Best regards, >> >> Maik >> >> >> _______________________________________________ >> 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 >
- 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