dvd-hq.info Forum Index dvd-hq.info
DVD & video forums
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Time display incorrect with VBR

 
Post new topic   Reply to topic    dvd-hq.info Forum Index -> Compression
View previous topic :: View next topic  
Author Message
core



Joined: 30 Dec 2004
Posts: 3
Location: Des Moines, Iowa

PostPosted: Thu 30 Dec 2004, 3:39    Post subject: Time display incorrect with VBR Reply with quote

I encoded my first "real" DVD the other day with TMPEGEnc using VBR with a max bitrate of 7000. I left the minimum at the default, which I believe was 0. When I play it on my Apex player, the displayed run time gets horribly inaccurate when fast forwarding. (It was nearly impossible to seek in Adobe Encore 1.0 to set chapter marks, but that's another story.)

Is this time display error just something I have to put up with if I am to use VBR, or is there some workaround? It's not a _huge_ deal of course, since it plays fine, but if I'm going to spend 12 hours making a DVD I want it to work the way it should. Would setting the minimum bitrate much higher solve this, perhaps 4000? And what about that "allow padding with bitrate is lower..." setting?

Thanks in advance.
Back to top
View user's profile Send private message
RMN
Site Admin


Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Thu 30 Dec 2004, 5:04    Post subject: Reply with quote

Padding and using different values shouldn't make much difference (although you should stick to a minimum of 2 Mb/s or so, to makesure the disc is compatible with older players). The problem with the time display is that, while fast-forwarding, some players simply count the bytes, instead of actually reading the file, decoding it, and reading the timecode.

Try the disc on a couple of other players. If it happens on all of them, it might be a problem with the disc's structure, but I suspect it's just your player that's "cheating", and not reading the actual timecode as it should.

RMN
~~~
Back to top
View user's profile Send private message Send e-mail Visit poster's website
core



Joined: 30 Dec 2004
Posts: 3
Location: Des Moines, Iowa

PostPosted: Fri 31 Dec 2004, 13:05    Post subject: Reply with quote

Thanks for the quick reply. This makes some sense. Haven't tried it on other players yet, but will do so. I _hope_ it just is just my cheap Apex player cheating... it may not be a quality player, but for $50 or so, the thing willl accept _anything_! (SVCDs and beyond, even though it's several years old.) I once burned a DVD folder in data mode and it happily played it -- don't know if that's "supposed" to happen but I was just glad it played at all.

The thing is, though, I don't seem to experience this problem when I play factory stamped DVDs? (Not that I nitpick them as much, of course.) I read somewhere that factory DVDs usually use CBR, but I'm not sure about that and can't now find the original article. Is this true? If so, why would they do this, if VBR is superior space-wise? I do have a dual layer burner, so if space is the _only_ issue I'll gladly pay for dual layer media. When I do a project for someone else, that is.

Anyway, thanks again for the reply. As a programmer I understand the complexities with VBR... I just wish it was a *bit* better supported by players, authoring software, and such.
Back to top
View user's profile Send private message
RMN
Site Admin


Joined: 04 Feb 2003
Posts: 587
Location: Lisboa, Portugal

PostPosted: Fri 31 Dec 2004, 20:54    Post subject: Reply with quote

Industrial DVDs have a higher reflectivity index and are easier to read, so it's possible the player is able to read the timestamp properly, instead of making a "guesstimate". Anyway, when you stop fast-forwarding, the player should show you the correct time even using recordable DVDs. If it doesn't, there might be something wrong with the DVD structure.

Also, if you play the DVD on your computer, you should get proper time dislay while seeking (PC DVD drives can read much faster, so the software always looks at the real timestamp).

About 90% of commercial DVDs are VBR (typically between 5 and 7 Mb/s average). If your player has a "monitoring" mode that displays the bitrate you can check this for yourself.

Dual-layer recordable DVDs are likely to have even more compatibility problems, because not many players were tested with them. The best disc type for set-top player compatibility is DVD-R (Maxell and Pioneer usually come ahead in compatibility testing).

RMN
~~~
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    dvd-hq.info Forum Index -> Compression All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Powered by phpBB © 2001, 2002 phpBB Group