[News]

News: emotionDV has upgraded to High Definition. Welcome to emotionHD!

[Kittihawk]

I kind of know some of the answer to this one and it relates to the really useful post recently about the optimal data rates in burning. But I have had a couple of faults that make me scratch my head a bit:

1) I burnt an 8 minute DVD via DVDSP at its default rates of 5.5. average and 7.5 max bit rate (under the encoding preferences). The source track came from a Quicktime movie exported from FCP 6.06 (I did not export it to Compressor on this occasion as an upgrade (I think) has caused a fault in Compressor that I did not have time to fix - more on this elsewhere). The video contained both Pal DVCAM movie images and JPEG stills. The resulting Quicktime was imported into the assets of DVDSP.

On two different domestic DVD players the DVD played back fine through all the video and most of the JPEG (I assume the JPEGS that started as large pictures were exported as DV by FCP and therefore would be identical in size to the rest i.e. 720 x 576) , however the DVD hung and stopped on one of the still pictures (the same in each player I think). I did another burn and dropped the average and max bit rates to 5 and 6 and the DVD worked all the way through. Why is this?  (NB this one was burnt on a 2008 iMac)

2) I amended another DVD that had seven MPEG tracks and replaced one of the seven with a Quicktime DV PAL track in the assets of DVDSP. The default burn rates of 5.5. and 6.5 were used in DVDSP. Total media time was about twenty minutes (tracks combined). Anyway the only track that did not play back properly was the one that was a Quicktime (.mov) in the assets. Again dropping the data rate to 5 and 6 did the trick and it all worked. What's going on? (NB this one was burnt on a Quad PowerMac )

3) A panning shot on one of the DVDs I've made with DVDSP MPEG 2 assets (two pass 90 minute setting on Compressor, bit rates about 6 and 7 ) looks awful - it stutters and strobes as the camera slowly pans across a room (none of that is present on the original DVCAM)  - all else is fine - again what is happening?  The room in question is very bright and the walls are white and there is a person moving in shot but I am not sure that has anything to do with it.

[Duane]

Good questions, possibly complex answers. I wish I could get to see your projects and assets because there are a lot of possible variables in your workflow.

Only thing I can suggest is going back and looking closer at what your assets are, how you are processing them, and what is happening. Most important, you need not to be starting with the question "Why does DVD SP not work?" in your head because it may well have nothing to do with DVD SP. In my job I produce many dozens of individual screener DVDs in a year and have not encountered problems like you are describing. This makes me question your process and assets.

It is a shame that you cannot go and take a course in DVD SP because from this posting, and others you have made, you would do well to get a better understanding of the process overall.

[Kittihawk]

Yep, I am sure you are right, I did a week's FCP Apple approved course about 4 years ago and it has been invaluable. Even a couple of days would be useful with a good instructor - I have learnt a lot from Lynda.com but it doesn't tackle all of the specific problems I mention.

My guess regarding the above is that some of the unencoded assets (i.e. not imported into DVDSP as MPEG but as a Quicktime movie in Pal DV format) produced a high data rate in some circumstances that the DVD players couldn't handle. I only did this for speed when I could not get Compressor to work after an upgrade. However it does reveal that the system is not always robust in allowing different workflows. I think DVDSP is pretty good in general and very willing to believe it is a problem on my part however the degree to which a programme forces one into that sort of conclusion is related to its "user friendly-ness".

[Duane]

Curious why the fact that some DVD players are incapable of playing data rates which are a standard of the DVD spec is the fault of DVD SP?

[Kittihawk]

Perhaps they are older? Maybe a 'name and shame' thread for DVD player performance would be useful?  I have four different machines for a start and, with regard to being able to play anything without stutter, I would rank them from worst (actually not too bad) to best: Hitachi, Panasonic, Sony and Cambridge Audio.

I notice some DVDs have phrases like "may not play on all machines" printed on the label.  I always assumed they are talking about different machine performance rather than restricted zones or different video standards? 

[Trevor]

I know there are many problems with players not playing home burnt dvds, even though they will play other burnt discs fine.

An interesting thing you said is that it stops on one of the stills on both players. As pure speculation perhaps the bit rate is too low at that point? This would cause the machine to run out of information in the buffer and freeze. But I don't know how they decide the intervals to read and fill the buffer with.

I do know that even the superbit discs run on an average of 6mb/s, so again perhaps you are just on the outside of that which gives some players problems. With all the available players out there, I find it hard to believe that everyone of them meets all the specs exactly and perfectly, which is why it's a good idea to stay well within the outer edge and not push the hardware to the limits.