Bitrate, compression & Quality

[Harrysmiith]

Sorry if this is really basic. I have searched but not yet been able to really understand this.

Using DVD RB and ECC basic I backed up a movie at 62.2% and ended up with a bit rate averaging just over 3000.
I am now backing up a movie and the reduction level is 57.1% with bitrates
8,808/2,300/4,336.
To me this means that even though the second movie had to be compressed more the average bit rate is significantly higher ? and so the output should be higher quality ?
Is 2,300 as the low figure still acceptable ?
Is pre processing really such a crime ? These 2 movies both have sereral episodes. It would be very easy to simply use shrink to remove the menus and extras and then use DVD RB to back up the main movies. But I understand that this can lead to problems ? I really have no time for extras and menus and would much prefer a higher bitrate ( assuming that that would be a good thing ?)

[blutach]

DBDRB (pro) can turn your extras into blanks. But a re-author in DVD Shrink would eliminate them entirely. Your choice. DVD Shrink does have a couple of little bugs in re-author mode, but nothing too much to worry about.

At an average BR of 4.3Mbps, the second is better. See http://forum.digital-digest.com/showthread.php?s=&threadid=45129 for a real basic explanation of exactly what you just described.

Regards

[Sir Didymus]

...And concerning pre-processing, no it is not a crime; the big warnings you may have got looking all around are due to the fact that (especially in the past...) it was a frequent situation to see in the forum reports of "bugs" just caused by self inflicted mistakes produced by pre-processing. So, BEFORE POSTING A SUPPOSED BUG, it was explicitely asked not to do pre-processing... Just to eliminate a possible source of mistakes from the equation...

Concerning Movie-only backups, please consider DVD-RB have a specific mode to do this, so no need of pre-processing with Shrink...

Me personally do PgcEdit+VobBlanker sessions before every one of my backups, in order to customise the title appearence and to get rid of silly intros...

Cheers,
SD

[Harrysmiith]

@ blutach. I will give shrink a go next time then. I have no need for extras and menus.

@Sir Didymus. One my 2 disks there are episodes rather than one movie. Going Movie only
picks one of the episodes and misses the others.

I know nothing about how these programs are written but if languages can be removed and sub titles removed would it be difficult to remove menus and extras ( with DVD RB) ?

[feedback]

I have a question about bitrates aswell, how do I interpet these figures?

- Reduction Level for DVD-5: 46,8%
- Overall Bitrate : 3038/2430Kbs
- Space for Video : 3285916KB
- Movie improvement from extra reduction = 19,9%
- HIGH/LOW/TYPICAL Bitrates: 3710/545/2430 Kbs

- Reduction Level for DVD-5: 46,8%
This means the original disc will need to be reduced to 46.8% of its original size in order to fit on a DVD-5.

- Overall Bitrate : 3038/2430Kbs
The average bitrate across the entire reencoded disc will be 3039Kbs on NTSC interlaced sections, otherwise it is 2430Kbs. Note that less bitrate is needed to get the same quality in a source that uses pulldown -- because fewer pictures are encoded.

- Space for Video : 3285916KB
The output disc will use this amount to store the video (only) portion of the output. This does not include the menus, IFO, BUP, audio, or subpicture portions of the output.

- Movie improvement from extra reduction = 19,9%
When using mechanisms to reduce the amount of space applied to extras (like "Half/Half" or "Steal Space") -- this is the level of improvement applied to the main feature as a result. Note that this can also be a flag if you are doing series discs... since the "Feature" is always considered to be the largest VTS -- trying to reduce "Extras" can actually hurt any of the episodes that aren't in the biggest VTS...

- HIGH/LOW/TYPICAL Bitrates: 3710/545/2430 Kbs
Each segment has an average bitrate assigned that is based upon its individual demand. These show the highest, lowest, and typical bitrates that are applied as the average to the segments.
__________________
I would never belong to a group that would accept someone like me as a member. [Groucho Marx]
The above is jdobbs answer to some bitrate questions.

The typical bitrate is more telling of what your movie will look like.

I wouldn't worry about the low bitrate value, (of the high,low, typical)
As one can see the above person had a low bitrate of 545 which is no big deal. You want to focus more on the typical over the others IMO.

You can also use the 'Video Segment Editor' to blank out the Extras manually.

When I backup an entire DVD I use it to blank the extras I don't want and I slideshow the credits at the end of the main movie for bitrate savings.

Regards,:)

[TomBrooklyn]

Me personally do PgcEdit+VobBlanker sessions before every one of my backups, in order to customise the title appearence and to get rid of silly intros...
I have been using VobBlanker and MenuShrink but not PgcEdit. What is the purpose of using PgcEdit before or after VobBlanker?

[TomBrooklyn]

Me personally do PgcEdit+VobBlanker sessions before every one of my backups, in order to customise the title appearence and to get rid of silly intros...

I use VobBlanker to get rid of unwanted intros and trailers and such also. What do you use PgcEdit for?

[blutach]

From the home page:

http://download.videohelp.com/r0lZ/pgcedit/index.html#introduction

Please consider looking at it.

Regards

[Sir Didymus]

@TomBrooklyn - sorry for the deferred reply - as blutach is pointing out, PgcEdit should be considered for all of the purposes where the old IfoEdit was used, and more...

For example it is very easy to strip unwanted language units from menus, to remove whole titlesets from DVDs, and so on...

These operations should be performed with some care, but the trace function, that I suggest to play with, is a fundamental and very nice tool to learn and make practice with DVD commands, navigation, structure...

@Harrysmiith - afraid for not replying before... I admit I did not catch your post - If you do not need menus and extras, for discs with episodes, I agree DVDShrink, in Re-author mode, is a good way to handle the title:
1.drag the episodes to left window;
2. set compression to "No Compression";
3. backup.

Then we may use DVD-RB to recode the backup...

:)

Edit: Thinking further at this, maybe the discussion can take the form of a feature request to Jdobbs for extending the backup modes of DVD-RB, including a "movie+" mode, where one or more additional titles are taken from the source DVD. The authoring should be built from scratch (like in movie only mode) with the aim of playing the selected titles one after the other, in a straight sequence... No idea if it is feasible, or too complex, however...