Transcoding and audio synch...
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2007-03-22, 03:57 PM
Frank Z
[COLOR="Gray"] I used to ask 'why?' Now I just reinstall... [SIZE="1"]______________________________________________ Author: ZTools: ZProcess, MVPServerChecker; UltraXMLTV Enhancer, Renamer, Manager; [/SIZE] [/COLOR]
2007-03-22, 04:29 PM
zehd Wrote:http://forums.nextpvr.com/showthread.php...hlight=pts That is an interesting thread. I wonder if the file he was having issues with played fine when streamed to his PC instead. It would also be interesting to know if popular software media players (Windows Media Player, PowerDVD, etcetera) use some other method (other than timestamps) to sync audio-to-video.
LAJams
Media Server: Server2003 Standard GBPVR (currently recording only) Asus P4P800-E Motherboard Pentium 4 CPU 1GB DDR400 Memory Hauppage PVR150 2x MediaMVPs
2007-03-22, 04:33 PM
lajams Wrote:That is an interesting thread. I wonder if the file he was having issues with played fine when streamed to his PC instead. It would also be interesting to know if popular software media players (Windows Media Player, PowerDVD, etcetera) use some other method (other than timestamps) to sync audio-to-video. Yes this is the issue that you and he, and we are experiencing. Plays fine on PC, trouble with MVP... And yet, it's not and MVP issue. It's a transcoder issue The transcoder is not creating a proper PTS... I think
Frank Z
[COLOR="Gray"] I used to ask 'why?' Now I just reinstall... [SIZE="1"]______________________________________________ Author: ZTools: ZProcess, MVPServerChecker; UltraXMLTV Enhancer, Renamer, Manager; [/SIZE] [/COLOR]
2007-03-22, 05:24 PM
zehd Wrote:Yes this is the issue that you and he, and we are experiencing. Plays fine on PC, trouble with MVP... And yet, it's not and MVP issue. It's a transcoder issue Are there any analysis tools that could display the PTS, or the internal structure of video files? I'd like to do a side-by-side analysis of my PVR150 recordings versus a DVD I ripped and transcoded to mpeg2. Anyone know of any, free or otherwise?
LAJams
Media Server: Server2003 Standard GBPVR (currently recording only) Asus P4P800-E Motherboard Pentium 4 CPU 1GB DDR400 Memory Hauppage PVR150 2x MediaMVPs
2007-03-22, 07:56 PM
Maybe this one could give you some extra info:
http://www.videohelp.com/tools?tool=MPEG_Validator
AMD Athlon 64 3000, HDD: 80, 120, 200 GB, Hauppauge 350 + 150, MVP, Asus 6000L Laptop client, Asus X50sl client,
Fritz!box 7140 modem/router, GBPVR 1.3.7.
2007-03-22, 09:23 PM
lajams Wrote:Are there any analysis tools that could display the PTS, or the internal structure of video files? I'd like to do a side-by-side analysis of my PVR150 recordings versus a DVD I ripped and transcoded to mpeg2. Anyone know of any, free or otherwise? We're really going to have to lose focus on ripped DVDs and focus on the output of a Transcoder. That's because, it's not AVI, WMV, VOB, that's the issue. It's the quality of the final result, not what goes in at the start...
Frank Z
[COLOR="Gray"] I used to ask 'why?' Now I just reinstall... [SIZE="1"]______________________________________________ Author: ZTools: ZProcess, MVPServerChecker; UltraXMLTV Enhancer, Renamer, Manager; [/SIZE] [/COLOR]
2007-03-22, 09:25 PM
HtV Wrote:Maybe this one could give you some extra info: That looks promising. It would be a way of seeing what were the parameters to encode a mpg from a tuner as opposed to transcoded... I'll look at it after work
Frank Z
[COLOR="Gray"] I used to ask 'why?' Now I just reinstall... [SIZE="1"]______________________________________________ Author: ZTools: ZProcess, MVPServerChecker; UltraXMLTV Enhancer, Renamer, Manager; [/SIZE] [/COLOR]
2007-03-22, 11:43 PM
Here's some of my random ramblings on this thread
I think the mvp does an amazingly good job decoding mpeg-2 files that are captured live. Sync problems are minimal - modern pc's simply decode the ac3 stream in vob's so you cannot use this as an indicator of transcoding quality. - I still haven't found a media extender that will replace the mvp yet. Sure some files can play vob's and dvd iso's but that is more a network dvd player and I want much more than this. Anything without h264/avc I consider a short term solution for HD. - Modern PC's will always be superior to $100-300 boxes for decoding new formats. - thanks to linux and open source for vlc/mplayer/ffmpeg for providing access to those formats that have been really been designed for Windows PC's. - if SageTV can do ac3 on the mvp so can mvpmc Martin
Well, I made some interesting progress this evening. I did more research on video/audio sync and found this proggie out there called Video Redo. Its a program that allows you to cut frames from mpeg files without recoding the entire file. It also has a unique function called "Quick Streams Fix", which analyzes the file, corrects errors, and writes out a new "fixed" file based on that.
I have a notoriously bad file of mine (a dvd rip of Cinderella 3, my kid's favorite) and ran it through this process. Its very fast, and took only about 1 minute to run an analysis of my file and output a "fixed" version. It reported back at the end that it removed two frames....a "Sync" frame, and one other...a "video" frame I believe. I'll re-run the process again in a couple hours to be sure. Anyway, I copied the file produced by this process out to my server under a new name, and it now has no sync issues. I've done several ff/rw, and forward and back-skips. I have also stopped the video, and resumed several times. The video and audio stayed in sync every time. Just to be sure, I went back to the old file, and ran it through a series of ff/rw and skips, and it only took a few times to get it out of sync. I then returned to my fixed file and repeated some harsh shuttling back-and-forth and no sync issues. I did percieve a *slight* loss in video quality in the new, fixed file, but I can't be sure. My big screen is being used by my kids to watch....Cinderalla. Go figure. I'll have to wait until after they go to bed to be sure. I've got some more checking to do, and I'm going to run a few more of my files through it, but it may prove interesting for others to have a look at this program. Here is the website: http://www.videoredo.com/. Download the trial version of the proggie, run the setup with all defaults. You will need to order a trial key. Although you can use the program completely, all the functions will only output around 40 seconds of video or so, until you get a trial key. Its free, so there's no outlay in trying. I'll be back later to report after the kids go to bed.
LAJams
Media Server: Server2003 Standard GBPVR (currently recording only) Asus P4P800-E Motherboard Pentium 4 CPU 1GB DDR400 Memory Hauppage PVR150 2x MediaMVPs
2007-03-23, 12:35 AM
lajams Wrote:I did percieve a *slight* loss in video quality in the new, fixed file, but I can't be sure.VideoReDo does not reencode the file except at the cut points. The file remains unchanged. The sync problems with the MVP have been around since day1. I'm fairly  active on the VRD and SHSPVR sites and have been using the products for quite a while and have beta tested the HVR1600 and the wireless MVP. VRD does an excellent job of cleaning up the Hauppauge files. I've not used it but there are com and batch processing capabilities so you might even be able to automate the cleanup process.
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