Lower Bitrate at credit-start ?

[Ripping]

Yes, i came from Divx-Section :D and so i know that it's possible (in Nandub) to reduce the video-bitrate at credit-start, from frame n to the end.
Now i create svcd (i'm still learning) with dvd2svcd (i love it :) ) and tmpg and only one (perhaps more later :D ) thing i miss, is that 'bitrate-reducing' in video-encoding.
I 've found not very much about this topic and i'm not sure that this is the right forum :rolleyes:

[UltimateDBZ]

There's no way to do this in DVD2SVCD at this time, perhaps a feature in a future version...

[markrb]

With Mpeg VBR encoding something like this happens as part of he encode. If the credits are just black back drops then not many bits are used anyway. Same thing for any really dark scenes oe the end credits.

As for forcing a lower bitrate there is no mpeg encoder that I know of that can do that.

Mark

[UltimateDBZ]

lol, yeh the last phrase of my posts assumes that in the future that would even be possible with MP-2 (doubtful). I was a bit unclear, sorry.

[Kandor]

that is not true, because divx works the sameway, just that you dont think that the bitrate it gives to the credits is tomuch for someones taste so the exact same can be with mpeg2.
so just lower the bitrate to the lowest and the upp the general bitrate in the movie will work with mpeg2 too so.

[chainsaw135]

@kandor i didn't understand anything you said, could you post it that again and make your post a bit more clearer?

[Abond]

I didn't understand either, but presumably they think about the way Gordian Knot deal with credits. In the preview window one could select the frame number with which the credits start, then this part of the movie is encoded with separate avs file 1 pass quality based at 20% quality. I think it is near the same as 20% CQ in TMPG, or 1 pass vbr with low quality settings in CCE. The actual movie is encoded with what one set for it, after completion both files are merged and audio is muxed. So probably kandor think that the same might be done for MPEG. Well, when I see how much problems people have to cut and merge mpegs, I think it is not worth, better to cut the credits out.

[Tobytl]

Well, you could always use the local bitrate setting in the advanced section of CCE. I am not sure if it helped any, but I would assume it left a whole lot more bits for the rest of the movie. I stopped this when I discovered dvd2svcd, the ease it provided overruled the benifits of that to me...

[markrb]

that is not true, because divx works the sameway, just that you dont think that the bitrate it gives to the credits is tomuch for someones taste so the exact same can be with mpeg2.
so just lower the bitrate to the lowest and the upp the general bitrate in the movie will work with mpeg2 too so.

I never said it was exactly like it. I just said with VBR if the scene is dark not many bits are used anyway.

I also said I know of no Mpeg encoder that can do this?
If you know of one or a way to do this please tell.

You maybe able to cut the movie up and encode sections differently, but have you ever seen a mpeg encoder that can ramp the bitrate? If so please tell.


Mark

[Kandor]

sorry for my unclear message but you would be able to do the same as gordian knot does with 2 avs files. one with the main movie and one with the credits alone and merge them togther.
I did'nt say it is worth it or it is easy just that it is possible.

[ux-3]

Originally posted by markrb
With Mpeg VBR encoding something like this happens as part of the encode. If the credits are just black back drops then not many bits are used anyway.

Sorry Mark, but unfortunately I cannot confirm this. I investigated the problem a while ago, when I was putting a movie with long credits onto an SVCD and had no interest in the credits. Since the chapter included the end of the plot AND the credits, I was setting the CD size to something big so that the actual CD would come to an end about half a minute into the credits. I had read about other suggestions, but this was a quick and dirty solution. The amazing thing was, that by using linear sentences, I would get the cut point pretty well dead on! In other words, it seemed that the credits are coded at about average bitrate. I downloaded bitrate viewer and took a "look" at the credits-bitrate. It was about average. So the bitrate is not lowered significantly during the credits. Perhaps others have more encouraging results, but I guess it will be similar.

[Tobytl]

Well, that was wierd. Taking a cue from ux-3 I checked out a couple of converts that were still on my hd with Bitrate Viewer, and something wierd came up. On The Count of Monte Cristo, during the credts scrolling the bitrate is around 2200 spiking up to 3000 when theres lots of text and down to 500 when theres no text, and the average for the whole movie was around 1600. And the same for 4 others. And all these movies are just white text scrolling upwards on a black background. Heh, so thats like 4 whole minutes of 2200kbps video. Maybe I should reconsider my stance on keeping the credits on my backups...

[markrb]

Yeah some credits have more motion and such then others do so these could cause the bitrate to go much higher.

Before you decide to cut the credits or not just spend a minute figuring out if the slight increase of bitrate is worth it to you to loose them. Only you can decide that for yourself.
On a 2 cd encode 4 minutes with 224 audio is about a 60 point video drop at 192 audio it's about a 55 point drop.

You also need to figuring if you are squeezing as it is. If you are trying to wring as much space out of the discs then that extra might be worth it, but if you are already near the max bitrate then it doesn't matter.


Mark

[ux-3]

Originally posted by Tobytl
On The Count of Monte Cristo, during the credts scrolling the bitrate is around 2200 spiking up to 3000 when theres lots of text and down to 500 when theres no text

Could you please enlighten a poor soul as to how you get that programm "bitrate viewer" to show you the cooresponding picture? I can't find out how to do this...
thanks

[Tobytl]

Oh sure, its a little complicated though, not difficult, just involved. As you move you mouse pointer over the graph area, the time will be displayed right underneath the average column. Convert this time to seconds and multiply by the real frame rate of the file (ie if NTSCFilm multiply by 23.976, pulldown doesnt affect bitrate viewer). Now that you got the frame number, create a dvd2avi project and an avisynth script that just uses mpeg2dec to open it, and open in virtualdub. Seek to the frame number you got previously.

There probably is a better way to do this, but its the only one i could think of. Oh and I have version 1.5.002 of Bitrate Viewer, if that makes a difference.

[winxi]

I also noticed that the bitrate in all of my credits is very high. (Usually highly above the average bitrate). A workaround would be to cut of the credits, encode them with a much lower bitrate, and then merge them to the main movie again (if you want to keep the credits, of course).

winxi

[ux-3]

I guess people in movie theaters just don't understand how important the credits are. While they leave, some here take great pain to keep them. Beats me...
The only thing that makes them worth keeping is a clever extro, as in Monster Inc., or a good soundtrack (Jurrasic Park, Chocolat). The former gets the regular encode, but for the later, I was thinking if it wasn't possible to just halt the movie, but let the music play. I've actually seen this done on a VCD. Though it seemed like a bug it could be made a feature...