DVD-Video compatibility
by Steve
on
Jul 22, 2004 at 6:16:05 pm
I'm thinking about buying a new dual layer DVD recorder, which at this point are not DVD-R compatible. (I have a DVD-R player). If I record in the DVD-Video format, is it compatible with the DVD-R format? Will it play on my player?
Re: DVD-Video compatibility by Jason Casey on Jul 22, 2004 at 6:25:31 pm
Currently the studies I have seen with the DL discs are showing terrible compatability, much like when DVD-R first came out. All the DL burners out right now will also record on standard +R discs. If you use the standard 4.7GB DVD+R discs you should get good compatability, not as good as DVD-R, but it still should play on *most* players.
Re: DVD-Video compatibility by Roadkill on Jul 23, 2004 at 12:04:34 am
Compatibility of DL discs doesn't seem to be so bad, but the burner has to be able to write DVDs with a "DVD-ROM" book type bitsetting. Dual layer DVDs that (correctly) identify themselves as "DVD+R DL" suffer from the same problem as DVD+R discs: many players don't know what a "DVD+R DL" is and as a result will refuse to play them.
Some burners that support the bitsetting trick are: Benq DW-830A and 1600A, NEC ND-2510A and the LiteOn SOHW-832S. Originally the Sony DRU-700A could do this too (with the help of a LiteOn tool), but with firmware update VY05 Sony has made this impossible.
Re: DVD-Video compatibility by Steve on Jul 23, 2004 at 6:46:19 am
Thanks for the posts. Regarding Roadkill's comments, just so I'm sure I understand... If I buy a current gen DL burner that only supports +R DL, and write a DVD-Video in the DVD-ROM format, I "should" be able to read this on a DVD-R player, correct? (Should in " " as I know there are individual compatibility issues...)
That raises another question - will DVD-ROM write dual layer on a DVD+R DL burner?
Re: DVD-Video compatibility by Roadkill on Jul 23, 2004 at 4:58:29 pm
The test on which I based my "compatibility of DL discs doesn't seem to be so bad" was published in the German computer magazine c't (available in print only). The results of their test are in the table below. (Way below - which seems to be the only place where the Cow wants to place a table.)
Steve,
I am sorry but I don't understand your last question "will DVD-ROM write dual layer on a DVD+R DL burner?"
Re: DVD-Video compatibility by Steve on Jul 24, 2004 at 12:41:43 am
To Roadkill:
Thanks for hanging in there with me. Sorry I was not clear. Let me try this another way.
My intent is to transfer personal videos to DVD, and also to record off the air HDTV broadcasts for playback via my DVD player. For HDTV, I need a lot of storage capacity.
My DVD player is a Toshiba, which uses the DVD-R format
The only dual layer drive available today is DVD+R.
So:
1. I'm assuming from your earlier post that if I create a DVD-Video and burn it using DVD-ROM format, that it should play in my DVD-R player. Am I correct?
2. Will I get the benefit of dual layer capacity if I record in DVD-ROM?
Re: DVD-Video compatibility by Roadkill on Jul 24, 2004 at 1:04:52 am
If your Toshiba set top player refuses to play DVD+R discs, it probably won't play DVD+R DL - no matter whether the disc identifies itself as +R DL or -ROM. (You could check whether or not it is supposed to support DVD+R media at DVDplusRW.org: Compatibility and VideoHelp Player Compatibility List. It will probably be a while until information for +R DL compatibility becomes available.)
The test I mentioned tested 80 devices of which 23 were set top players, including 1 Toshiba player: the SD-140E. This one did play the DL disc.
To Q1 and Q2: you won't be burning in DVD-ROM format. The disc will be a dual layer DVD+R DL either way. The only difference is that with the bitsetting trick, the disc will identify itself as "DVD-ROM" (little white lie) instead of "DVD+R DL" (true) to the playback device.
Re: DVD-Video compatibility by Trai Forrester on Jul 27, 2004 at 9:50:47 am
Hi Roadkill,
Guess what? As I was digging around in the spec awhile ago, I may have found something possibly interesting, and have been wanting to test it out;
In the VMGI_MAT (Video Manager Information Management Table), and each VOBU_ADP_ID (VOB Adapted Disc Type), there's an option in the DSI_GI (Data Search General Information) for each VOB (must match the VMG setting) to be flagged as "adapted" for either DVD ROM or DVD-R/-RW; i.e. replicated or recordable.
I wonder if we were to change the flag here just like we do the bit setting on DVD+R's in the lead-in, we could increase compatibility even further!?
My program isn't set up to give user access to this data field in the VOB, at the moment, but after we get a few things we're working on right now done, this could be arranged!
Think it's worth a shot? (you know, it's been awhile since I blackened a freshly pressed lab coat! :-)
Re: DVD-Video compatibility by Roadkill on Jul 27, 2004 at 10:52:04 pm
Trai,
Sounds so deliciously technical that it must be worth a shot! ;-)
Is there any authoring app that sets this flag and more importantly: would there be any app that actually adapts the VOB according to disc type? What would the adaptation involve? Without knowing how the VOB is or isn't changed, manipulating the flag could possibly have a detrimental effect on playback compatibility, or it may do nothing at all (set top players may be unaware of the flag's existence).
There seems to be still a lot of dark matter in the spec.
Re: DVD-Video compatibility by Trai Forrester on Jul 28, 2004 at 12:46:42 am
Hi Roadkill,
I don't know much about this, frankly. But I think that you're correct that a lot of players won't read the flag. For sure, the older players won't know what DVD-R is, as this book wasn't specified until over a year after the first players shipped. That's why the bit setting on the +R format works so dramatically; but that's for the lead-in, which all players must read.
The Spec says:
"VOBU_IDP_ID -
Adapted Disc Type: Describes the type of a disc to which this Part 3: VIDEO SPECIFICATIONS is adapted"
It goes on to describe "identifiers" in the main VMG IFO files and in the Navigation Packs in the VOB, that are supposedly there to tell the player what kind of platter is playing in it.
Since I replied to you, I checked a DVD Studio Pro written DVD-R in TFDVDEdit 1.0 (our first version of the app was like IFOEdit, showing all the gory details) and it did not set this field to identify the disc as a recordable. I don't know if any other app does.
My theory now (uh, oh :-), is that since DVD-R first came out with a 3.95 disc size, which has the same data holding pit length and width (and data capacity) as one of the layers on a dual layer disc, and the two also have the same reflectivity rating, that a flag was introduced in the spec to compensate for the smaller pit and larger data size DVD R General disc, when it was introducted later, and to tell the player...to slow down it's spin!
Right now (with the current level of our DVD spec knowledge) we have to lower the bit rate because of the smaller data pit sizes on DVD-+R (4.7GB), because it's harder for the player to pull data off the platter with smaller data pit sizes (to jump from a capacity of 3.95G to 4.7G over the same surface area) with the less reflective DVD recordable disc (both + and - R).
What leads me to this conclusion, is if you check the specs for DVD-R, it has the same "channel bandwidth" capacity (ability to be read by the player) as a more reflective replicated DVD-ROM! But we know in the real world, that the lower the bit rate, generally the higher the percentage of compatibility is had. So I couldn't figure out for the longest time what was up; why didn't the specs of the DVD-Recordables state this reality; the need for lower bit rates on them?
So unless Pioneer and the gang is pulling another fast one on us, these identifiers must slow down the velocity of the rotation of DVD-recordable in the newer players, just a tad; to make it easier for the player to read the data of the more data compacted, LESS REFLECTIVE, recordable with 4.7 G of data (not a problem getting data off the same data pit size of the ultra reflective replicated disc).
My next experiment after we get '3 out of beta, is to write a +R disc with the compatibilty bit set (that will get playback started on the older players), still with a moderate bit rate (keep compatibilty with older players)...and to flag the DVD +R disc as a DVD-Recordable; this might be the margin that makes some borderline players compatible!
We'll see, huh? (the risk of a blown beaker on this one doesn't dissuade me one bit :-),
Re: DVD-Video compatibility by Trai Forrester on Jul 28, 2004 at 1:54:54 pm
Oh Roadkill,
Or, maybe the flags tell the DVD players' laser and/or decoder to do something to account for the less reflective media?
....still thinking (maybe I'll give the boys in Japan a call? :-)
Yes, the DVD-Video Spec is all about fun. Example: one reason DVD-9's caused so many problems over the years for Sonic, who corrected their mistake early, Astarte (DVD SP 1.x), Apple, Gear Software; and hopefully not Roxio, Nero and others), is this is the only thing said about layer breaks in the entire DVD-Video Spec (found in Part III: VIDEO SPECIFICATION - 3.1 Logical data structure of DVD-Video disc, page VI3-5):
"3.1.5 Relation between Logical Structure and Physical Structure
The following rules appy to Cells:
1) A Cell shall be allocated on the same layer.
2) Two Cells which are presented seamlessly shall be allocated on the same layer."
That's it. The layer break is not explicitly defined in the DVD-Video spec! But from the above, it's easy to figure out that layer 1 must begin with a Cell (to satisfy rule 1) and this Cell that's to act as the layer break, needs to be flagged non-seamless, right? :-)
But Apple seems to be the only ones that still don't get it, they have an option in the format window in DVD SP 3 to flag the layer break Cell as seamless, violating DVD Spec rule (and it will not work on high percentages of players, depending on the bit rate and GOP Structure of the stream playing through the break)! Oh well. :-)
Re: DVD-Video compatibility by Roadkill on Jul 29, 2004 at 12:44:04 am
It would be great if the flag told the player it has to expect a less reflective disc - assuming that the player could do something useful with that information. But the text seems to be saying that the flag is an indication for an "adapted" VOB. I am still wondering how or even if a VOB could be adapted. ???
A thought about the 3.95GB DVD-R being similar to one layer of a DVD-9: There could be some similarity, but DVD-9 still has 4.27GB per layer. And where the capacity reduction (compared to 4.7GB) of a DVD-9 is caused by the increased pit length, isn't (I almost wrote "wasn't") it the wider track pitch that made a DVD-R 1.0 hold less than 4.7GB?
"A Cell shall be allocated on the same layer." Wonderful. It almost tempts me to splurge on a spec Book. ;-)
Re: DVD-Video compatibility by Trai Forrester on Jul 29, 2004 at 4:05:48 am
Hi Roadkill,
More specifically (and accurately) , this Adapted Disc Type info in the VOB is located in a "DSI_GI" (Data Search Information General Information) which is just the "general info" for a larger Data Search Information (DSI) packet that resides at the Navigation Pack level of the VOB. The "Nav Pack" occurs on every VOBU (VOB unit) in the VOB; about once every half second. Here's what the info this DSI_GI describes (contains 32 bytes worth of data):
1) NV_PCK_SCR - System Clock Reference of Nav Pack
2) NV_PCK_LBN - Logical Block Address of Nav Pack
3) VOBU_EA - End address of VOB Unit
4) VOBU_1STREF_EA - End Address of the first Reference Picture in VOB Unit
5) VOBU_2STREF_EA - End Address of the second Reference Picture in VOB Unit
6) VOBU_3STREF_EA - End Address of the third Reference Picture in VOB Unit
7) VOBU_VOB_IDN - VOB ID number of the VOBU
*8) VOBU_ADP_ID - VOBU Adaption Identifier* <----- this is our guy
9) VOBU_C_IDN - Cell ID number of the VOBU
10) Cell_ELTM - Cell Elapsed Time
The whole DSI (Data Search information table) Packet includes (again, this occurs about twice a second - depends of number of frames in the GOP):
DSI_GI - DSI General information - 32 bytes - <---- contents listed above
SML_PBI - Seamless Playback Information - 148 bytes
SML_AGLI - Angle Information for seamless playback - 54 bytes
VOBU_SRI - VOB Unit Search Information - 168 bytes
SYNCI - Synchronous Information - 144 bytes
reserved - 471 bytes (big ole blank spot? :-)
Total DSI packet size - 1017 bytes
Each of the above headings have a whole bunch of data in them, just like I listed the DSI_GI's contents.
Then, along with this DSI Packet (DSI_PKT), which occurs twice a second in the VOB, remember; there's also a PCI packet (Presentation Control Information) occuring twice a second also, one for each Nav Pack. It has all kinds of goodies listed in there:
PCI_GI - Presentation Control Information general information - 60 bytes
NSML_AGLI - Angle Information for non-seamless playback - 36 bytes
HLI - Highlight Information - 694 bytes
RECI - Recording Information - 189 bytes
Total PCI packet size - 979 bytes
Each of these headings in the PCI are crammed with all kinds of data, including, interestingly, a flag which depends on the setting of the "adapted disc type" (VOBU_ADP_ID) over in the DSI: Macrovision can't be set for "on" if the adapted disc type is set for DVD Recordable.
Here's what we show for each Nav Pack in the VOB in TFDVDEdit. We have combined the data from the DSI and PCI for each Nav Pack to show to the user, what we've thought and has been requested and might be useful to be able to change (and copy and paste any changed settings into all the other Nav Packs of the particular VOB, by Cell boundary). We've got several things slated to be added here (what we're discussing, if the tests prove it worthwhile, right? :-), including the ability to attach specific audio streams to angles, so the remote angle key changes audio streams as well as the angle:
The Nav Pack has shown to be so important, that Ben Weinrach, Ian Shepherd, and Jake Russell formed the "Nav Pack" group at NAB! Here's what Ben Weinrach says about the Nav Pack group in the intro to his department (http://www.tfdvdedit.com/public/department38.cfm) over at the TFDVDEdit support site:
"Way back at NAB 2004, a group of us casually formed a contingent we called “The Nav Pack”. Our objective: to push and abuse the DVD Spec in ways that can only be accomplished with TFDVDEdit. Unlike authoring applications, we now have direct access to the smallest unit of the DVD structure, the nav pack. There are numerous parameters to experiment with - many of which are directly related to the way overlays are displayed. At NAB, The Nav Pack tossed around some exciting ideas for ways to use this unique capability, and hopefully I’ll be able to share some of them here – once we know they work, of course… :)"
I think membership in the "Nav Pack" if free, btw :-)
So the point is, since this Adapted Disc Type data field is listed in among dozens (maybe hundreds) of parameters (that are read by the player twice a second) that ABSOLUTELY control what the player does in regards to the VOB it's playing back, and that this Adapted Disc Type setting is also located in the Video Manager, and must match the settings in the Nav Packs, this tells me that the setting is more than just window dressing. If so, then maybe, just maybe, we can help the player (surely there's some players that do something with the data?) playback our DVD recordables a little better, if these flags are properly set.
Thanks again,
Trai
PS. And thanks for the correction on the dual layer and DVD-R 1.0 data sizes. They're for sure not the exactly the same, like I said. I wasn't aware completely about their pit geometry. But a slightly wider pitch of the same length pits could definitely account for the data size total difference.
Re: DVD-Video compatibility by Trai Forrester on Jul 30, 2004 at 8:47:07 pm
Hi Everyone,
Just so you know, the TFDVDEdit programming team is implementing the correct writing of VOB identifiers for projects into the TFDVDEdit 3 DLT Pre-Mastering Edition beta, as we speak.
We're going to identify for DVD-+R by preference setting when the VIDEO_TS is loaded, for those occasions when you're using a third party app to write to DVD recordable, and for DVD-ROM, in all cases, as the program pre-masters to DLT. DVD SP doesn't write these fields properly it seems, even for to-be DVD-ROMs. There's actually a mismatch in the first few projects we've tested; the VMG is flagged for recordable and the VOBs as ROMs!
So, no matter what the upcoming tests prove, we're going to do it right (I certainly feel better about this decision! :-).
Re: DVD-Video compatibility by Trai Forrester on Aug 2, 2004 at 1:36:21 am
OKie dokie. Got her added in:
Above shows TFDVDEdit 3 DLT Pre-Mastering Edition beta, writing a DVD-9 project to two DLT drives at the same time; and you notice that the disc is identified as a DVD-ROM. The reason the data field is ghosted and not changeable, in the above screenshot is the project is getting written to disc at the moment. This can be changed to DVD-recordable of course, if you're not writing to DLT, and all the VOBs thousands of Nav packs will be striped with the correct identifiers.
Re: DVD-Video compatibility: UPDATE by Trai Forrester on Aug 2, 2004 at 9:49:21 pm
Hi Everyone,
Just so you know, DVD SP is correctly flagging it's images when writting to DLT's for replication (not setting anything, leaving a value of zero gives you the correct input for DVD-ROM).
It's the value for DVD-Recordable that the incorrect default value is left (the last two non reserved bits in the data field needs to have a value of "01" for DVD-Recordable).
My apologies (I didn't mean to give Apple DVD engineers heart palpitations :-),
Trai
PS. Btw, I'm keeping the thread going here because this is where I'm sending parties who would like an introductory to this possibly interesting setting. One way we're going to test it is to see if it helps the DVD+R DL discs be more compatible.
