unsubscribe -------------------------------------------------- From: <[email protected]> Sent: Monday, October 26, 2009 4:03 AM To: <[email protected]> Subject: Libmpeg2-devel Digest, Vol 31, Issue 1
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(Bikramjeet Singh) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 22 Sep 2009 14:59:22 -0400 (EDT) > From: Keith Winstein <[email protected]> > Subject: Re: [mpeg2-dev] Fwd: segfault on bad pictures / low link > power > To: ??baran Ak?ay?r <[email protected]> > Cc: [email protected] > Message-ID: <[email protected]> > 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 <[email protected]> >> 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 <[email protected]> > Subject: [mpeg2-dev] writing user_data() into an elementary stream > To: [email protected] > Message-ID: > <[email protected]> > 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 <[email protected]> > Subject: [mpeg2-dev] Video display is not visible. . . . > To: libmpeg2-devel <[email protected]> > Message-ID: > <[email protected]> > 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel > > > End of Libmpeg2-devel Digest, Vol 31, Issue 1 > ********************************************* ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel
