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[mpeg2-dev] unsubscribe Re: Libmpeg2-devel Digest, Vol 31, Issue 1
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From: Gus I. <gu...@gh...> - 2009-10-26 12:38:04
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unsubscribe -------------------------------------------------- From: <lib...@li...> Sent: Monday, October 26, 2009 4:03 AM To: <lib...@li...> Subject: Libmpeg2-devel Digest, Vol 31, Issue 1 > Send Libmpeg2-devel mailing list submissions to > lib...@li... > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel > or, via email, send a message with subject or body 'help' to > lib...@li... > > You can reach the person managing the list at > lib...@li... > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Libmpeg2-devel digest..." > > > Today's Topics: > > 1. Re: Fwd: segfault on bad pictures / low link power > (Keith Winstein) > 2. writing user_data() into an elementary stream (anand meher) > 3. Video display is not visible. . . . (Bikramjeet Singh) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 22 Sep 2009 14:59:22 -0400 (EDT) > From: Keith Winstein <ke...@MI...> > Subject: Re: [mpeg2-dev] Fwd: segfault on bad pictures / low link > power > To: ??baran Ak?ay?r <is...@gm...> > Cc: lib...@li... > Message-ID: <alp...@dr...> > Content-Type: text/plain; charset="utf-8" > > Hi ??baran, > > That video doesn't crash mpeg2dec or libmpeg2. It does have a heck of a > lot of corruption! And it is unusual in that it's encoded using field > pictures instead of frame pictures. > > As a practical matter, you need to reconsider how you're sending this > stuff if you want to get usable video. You need forward error correction, > retransmissions (like what TCP would give you), more link power per bit, > or something. > > On the theory for the crash, my hunch is that VLC is not engineered to be > robust against streams that use field pictures and don't observe the > required field sequence. (E.g., you have to follow a top-field picture > with a bottom-field picture, and this stream has so much invalid data that > it doesn't always do that.) > > Why are you using field pictures anyway? This is a pretty nasty stream and > it is going to touch a lot of code paths that free software is not well > tested on. > > Anyway, as a formal matter, mpeg2dec seems to be handling this properly > (and not crashing). If you want to stop VLC from crashing, my guess is you > need to switch to frame pictures. (You can still encode interlaced video > this way, of course!) And if you actually want usable video, you need some > of the practical improvements above... > > Happy hunting, > Keith > > On Tue, 22 Sep 2009, ??baran Ak?ay?r wrote: > >> 2009/9/8 Keith Winstein <ke...@mi...> >> Hello ??baran, >> >> >> Helloes again, >> >> If you feed libmpeg2 bad data (e.g., if you're dropping >> packets and not replacing them), you will certainly see green >> blotches -- that's generally what you see when there's >> missing intraframe data. >> >> (There are more sophisticated ways of doing error concealment >> in the presence of unreliable transport, but this is the >> basic behavior.) >> >> You shouldn't be able to make libmpeg2 segfault, though -- it >> should simply detect the invalid elementary stream. Can you >> capture the exact data you're feeding into it (after the UDP >> reception) and find a replicable segfault? Then we can debug >> it. Otherwise, no offense, it's probably a bug in VLC. :-) >> >> >> It's been a while, sorry, i didnt have time for video stuff, but now i >> captured some video that causes crash with vlc, splitted it so you can >> instantly see the crash :) >> >> Can you please check if you can reproduce this crash, and comment on what >> is causing this ? >> >> http://www.ish.kodzilla.org/minimum-crash.mpeg >> >> Best, >> Keith >> >> >> Thank you, best regards >> i?baran >> >> ps: dammit i first forgot to add video, than to "reply all" :S >> >> > > ------------------------------ > > Message: 2 > Date: Thu, 22 Oct 2009 23:48:22 +0200 > From: anand meher <kvm...@gm...> > Subject: [mpeg2-dev] writing user_data() into an elementary stream > To: lib...@li... > Message-ID: > <e84...@ma...> > Content-Type: text/plain; charset="iso-8859-1" > > Hello everyone, > I am working on a project using libmpeg2 where I > need to inject an explicit user_data() field with some text , > after every gop header in the input stream. I could inject the start code > 00 > 00 01 B2 which indicates a user data right after the GOP header is > finished > ( i.e by looking for the next start code occurrence after the GOP header). > *The problem is that i dont know how can i write a > simple > text inforamtion right after the start code 00 00 01 B2 in the user_data() > field ?.* (for example i would like to add something like a closed > caption > text describing the GOP) . Can some one help me with some pointers to some > links which say how an user data field can be constructed with simple > text. > > *also can some one tell me if there is a player/decoder which recognizes > the user_data text and displays on the screen along with the video*. I > hope > its not out of context with libmpeg2 forum. > > thanks in advance, > anand > -------------- next part -------------- > An HTML attachment was scrubbed... > > ------------------------------ > > Message: 3 > Date: Mon, 26 Oct 2009 13:32:49 +0530 > From: Bikramjeet Singh <bik...@lo...> > Subject: [mpeg2-dev] Video display is not visible. . . . > To: libmpeg2-devel <lib...@li...> > Message-ID: > <827...@ma...> > Content-Type: text/plain; charset="iso-8859-1" > > Hi There , > I am new to libmpeg2. library. First time i > have tried the "./mpeg2dec" and while giving it a TS file. but It is > giving video output in a very disturbed way even we cant see anything, > FramPerSeconf rate is very high some ware around 118fps. > > In the second test I multicast a mpg file using VLC player and modify the > "mpeg2dec" code to receive a multicast stream and again the same output > well > having the lower fps rate. because this time frame rate is limited by the > VLC player. Please help me wy i am getting this king of result. > I have attached the screen Shoot of the output result for better > understanding. > > Thanks in advance... > > > > > > > Thanks and Regards > Bikramjeet singh > > Logic Eastern India Private Limited > B-2, Sec- 31, Noida > http: www.logiceastern.com > Phone: +0120-2455112 > ext: 212 > Mobile +919971030527 > -------------- next part -------------- > An HTML attachment was scrubbed... > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: ScreenShoot_5.JPG > Type: image/jpeg > Size: 40079 bytes > Desc: not available > > ------------------------------ > > ------------------------------------------------------------------------------ > Come build with us! The BlackBerry(R) Developer Conference in SF, CA > is the only developer event you need to attend this year. Jumpstart your > developing skills, take BlackBerry mobile applications to market and stay > ahead of the curve. Join us from November 9 - 12, 2009. Register now! > http://p.sf.net/sfu/devconference > > ------------------------------ > > _______________________________________________ > Libmpeg2-devel mailing list > Lib...@li... > https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel > > > End of Libmpeg2-devel Digest, Vol 31, Issue 1 > ********************************************* |
