Re: [mythtv-users] A/V out of sync due to dropped frames
On Apr 6, 2005 10:21 PM, Justin Gombos [EMAIL PROTECTED] wrote: Wouldn't it be better in that case to reconstruct the missing video frames, rather than drop audio frames? Missing video frames can probably be reconstructed by interpolating the 'before' and 'after' frames, no? Yes, but it won't look the same -- and you can gently drop some audio frames over a larger period of time without it being noticable. WRT to your Plextor ConvertX it sounds to me like a USB bandwidth issue since it is an external device -- are you sure it is working at USB2.0 speed? USB1.1 speed is -just- enough for it to work most of the time (11mbps theoretical is dangerously close to what you would be recording at -- 3-5mbps..). -- Ian Trider [EMAIL PROTECTED] ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] A/V out of sync due to dropped frames
On Apr 6, 2005 10:27 PM, mary wright [EMAIL PROTECTED] wrote: There's a really good program called ProjectX it's a java app with fixes most errors in av sync'ing .It hasn't failed to work on eveything I have thrown at it .once I get the output from Project X I use Avidemux2 to edit and re-encode to what ever format needed Thank you for telling us about this program -- it is -EXACTLY- the sort of program I am talking about. Maybe you could put as compiled version up on the Internet somewhere (or I can -- if you can e-mail it to me). -- Ian Trider [EMAIL PROTECTED] ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] A/V out of sync due to dropped frames
On Wed, Apr 06, 2005 at 08:21:21PM -0600, Justin Gombos wrote: BTW- I'd like to point out that this problem seems to occurr with the Plextor tv402u. Sometimes part way into a capture video will get quite choppy, and audio out of sync, which is probably a symptom of the problem you describe. I just wanted to point that out, so folks buying a Plextor ConvertX are aware that the bundled software is not smart enough to resolve this problem. This does sound like your CPU or USB bus is overloaded and can't process the received streams quickly enough. Are you seeing dropping frame messages in your syslog? You're right, the gorecord app in the SDK doesn't handle dropped frames at all, but it was never intended to--it's just example code. Does MythTV resolve this problem? Presumably. It's the same issue all capture devices have when they don't get serviced often enough and experience buffer overruns, so any real recording app should be able to handle the situation properly. -Nathan pgpiZe6HDXIqj.pgp Description: PGP signature ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] A/V out of sync due to dropped frames
If you use Windows, there's an application called PVAStrumento that does the same thing as ProjectX. Recent versions of PVAStrumento have restored audio sync in 100% of the files I have used it on. I just use the default settings; select the .nuv file, 'make ps', set the output file, set 2048 as the packet size, and 'Start'. Link: http://www.offeryn.de/dv.htm mary wright wrote: There's a really good program called ProjectX it's a java app with fixes most errors in av sync'ing .It hasn't failed to work on eveything I have thrown at it .once I get the output from Project X I use Avidemux2 to edit and re-encode to what ever format needed ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
[mythtv-users] A/V out of sync due to dropped frames
* Ian Trider [EMAIL PROTECTED] [2005-04-05 20:58]: BTW, essentially if the problem you are referring to is audio sync, it is because of how the PVR-250 outputs streams -- the video and audio are aligned with via the PTS data, essentially timestaps, which dicates the temporal relationship between audio and video in an MPEG elementary stream. If something bad happens (i.e. a frame drop) the PVR-250 takes no notice of it; it will be indicated in the PTS data and the player deals with keeping the sync locked together. This isn't really wrong, and in fact seems like a good way to produce perfectly synced audio (because the temporal position of each frame of audio or video is indicated), but because most editing programs simply disregard this and work on the raw video and audio streams, you get 'issues' -- the lengths won't be exactly the same due to recording flaws (like frame drops) and it will go out of sync. The way to fix it is to have a program go through and readjust lengths of the audio and video so that the raw streams sync properly -- by dropping audio or video frames to make the actual video and audio streams match the PTS data. Wouldn't it be better in that case to reconstruct the missing video frames, rather than drop audio frames? Missing video frames can probably be reconstructed by interpolating the 'before' and 'after' frames, no? BTW- I'd like to point out that this problem seems to occurr with the Plextor tv402u. Sometimes part way into a capture video will get quite choppy, and audio out of sync, which is probably a symptom of the problem you describe. I just wanted to point that out, so folks buying a Plextor ConvertX are aware that the bundled software is not smart enough to resolve this problem. Does MythTV resolve this problem? ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
Re: [mythtv-users] A/V out of sync due to dropped frames
There's a really good program called ProjectX it's a java app with fixes most errors in av sync'ing .It hasn't failed to work on eveything I have thrown at it .once I get the output from Project X I use Avidemux2 to edit and re-encode to what ever format needed I also have a wrapper script that output's *.mpg but haven't worked out a way to get mythtv to run it on recorded programs If you want the link to a compiled ProjectX email me On 7/4/05 12:21 PM, Justin Gombos [EMAIL PROTECTED] wrote: * Ian Trider [EMAIL PROTECTED] [2005-04-05 20:58]: BTW, essentially if the problem you are referring to is audio sync, it is because of how the PVR-250 outputs streams -- the video and audio are aligned with via the PTS data, essentially timestaps, which dicates the temporal relationship between audio and video in an MPEG elementary stream. If something bad happens (i.e. a frame drop) the PVR-250 takes no notice of it; it will be indicated in the PTS data and the player deals with keeping the sync locked together. This isn't really wrong, and in fact seems like a good way to produce perfectly synced audio (because the temporal position of each frame of audio or video is indicated), but because most editing programs simply disregard this and work on the raw video and audio streams, you get 'issues' -- the lengths won't be exactly the same due to recording flaws (like frame drops) and it will go out of sync. The way to fix it is to have a program go through and readjust lengths of the audio and video so that the raw streams sync properly -- by dropping audio or video frames to make the actual video and audio streams match the PTS data. Wouldn't it be better in that case to reconstruct the missing video frames, rather than drop audio frames? Missing video frames can probably be reconstructed by interpolating the 'before' and 'after' frames, no? BTW- I'd like to point out that this problem seems to occurr with the Plextor tv402u. Sometimes part way into a capture video will get quite choppy, and audio out of sync, which is probably a symptom of the problem you describe. I just wanted to point that out, so folks buying a Plextor ConvertX are aware that the bundled software is not smart enough to resolve this problem. Does MythTV resolve this problem? ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users ___ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
