Recording from TV cards to Author to DVD

[Grandpa Broon]

For many years I have been working with DV video, firstly by writing to VHS tape and more recently authoring to DVD. I have used Adobe products during all that time and had no real problems until I decided to burn TV recordings using a DigiTV card.

Using Adobe Encore in the past, although it has it's limitations is fairly easy to use all round for DVD authoring. The problem I am having and indeed from many web boards others are having is only with Mpegs recorded from TV cards and not limited to one particular make of card or make of authoring software eg ReelDVD and Encore among others. Also the end result still makes a perfect DVD.

The problem: When the imported elementary files are played from the timeline everything works ok and is in sync. But when you scrub from the timeline to enter a chapter point and then play from that point only the sound runs from that position but the video runs from where you started scrubbing. If that was 10 minutes on, then the audio and video are 10 minutes out of sync. If you go back to the home postion and play the timeline again then it plays perfectly and you can author it perfectly too. But it makes inserting chapter points impossible.

This does not occur on any other elementary files I import whether from Premiere or if using other 3rd party software conversions, only digital TV mpegs. If I import using (audio + video) mpegs then this problem doesn't occur only on elementary files. The only problem with this method is that it doesn't produce AC3 audio but mpeg audio so it's not acceptable.

I know that TV cards save in mpeg-transport but DigiTV card and VRD both have converters and DigiTV now can save as DVD compliant files on the 3.12b4 version. Has anybody else had this or similar problems with their DVD authoring procedures using this or similar methods.

On Adobe forum many reports of this but nobody has come up with a solution and as Encore is mainly used for DV to DVD authoring none of the support people seem to be able to replicate it.

Regards David

[DanR]

First, how do you get the AC3 audio from the MPEG audio, and why isn't MPEG audio acceptable to you?

2nd, if you want to upload a couple short elementary streams, one from DV and another from DigitTV I'd be glad to look at them.

[Grandpa Broon]

Thanks for the reply Dan

AC3 or Dolby Digital is more compressed thus allowing more video on the DVD. AC3 also provides me with the same surround sound produced by the BBC whereas mpeg audio only gives me stereo. Although I use PAL, I thought that in NTSC, mpeg audio was not DVD compliant only AC3.

I'll send you an email when I have something for you to try Dan. But I have always used elementary files for the flexability and the fact that most author programs prefer it.

Cheers David

[DanR]

I'm not sure that AC3 is more compressed than MPEG audio. I'll have to check that out, but even if it is, then the difference is small compared to the size of the video stream.

If you are recording in MPEG stereo, then recoding, any conversion to AC3 will still be in stereo. In fact the recode can cause some quality loss.

MPEG (Layer 2) audio is mandatory for PAL DVDs. Its it not mandatory for NTSC DVDs, but I've yet to come across a player that won't handle it.

[Grandpa Broon]

Dan, I've posted a file on your site but it was truncated half way through the upload, so I'm not sure whether it's any good.

I meant to say that I contacted Nebula on this and their reply was to use Ulead Movie Factory.

Thanks for all your help

Regards David

[Adam]

Hi David,

As a side note, I didn't know that BBC Freeview (or some of them) are broadcast in Surround Sound. How do you know which programmes are braodcast in such a format, and is all Freeview broadcast in AC3.

Cheers,
Adam

[Lester Burnham]

Thanks for the reply Dan

AC3 or Dolby Digital is more compressed thus allowing more video on the DVD. AC3 also provides me with the same surround sound produced by the BBC whereas mpeg audio only gives me stereo.



Well there's no reason why surround sound (Prologic) isn't decodable from stereo in mpeg - because unless it is discrete multi-channel in DD, then it is multiplexed within the stereo signal. Therefore it doesn't matter whether the stereo signal is carried in AC3 / DD or mpeg.

Well apart from the fact that a flag can be set in an AC3 stream to signify that it's "surround".

[Lester Burnham]

I'm not sure that AC3 is more compressed than MPEG audio. I'll have to check that out,


Well the point of DD is to have something more compressed than MPEG. I think higher bitrates are allowed in DD, and again more so with dts.



but even if it is, then the difference is small compared to the size of the video stream.



Agreed, but if you wanted to get the most out of the space available... I mean there's a reason why DD is used on commercial DVDs - althouh mainly it's the discrete multi-channel thing.

[Lester Burnham]

Hi David,

As a side note, I didn't know that BBC Freeview (or some of them) are broadcast in Surround Sound. How do you know which programmes are braodcast in such a format, and is all Freeview broadcast in AC3.

Cheers,
Adam



Freeview *isn't* broadcast in AC3. I think that would be outside spec.

It may be mpeg stereo with surround encoded / multiplexed in (ie prologic) - but that's just a stereo signal.

The only broadcaster in the UK that uses AC3 / DD is Sky and even then it's only on certain channels and certain programes, and you'll need Sky+ to be able to use it.

[DanR]

The bit densities on MPEG1 audio and AC3 are identical. 0.0625 bytes / msec of audio at a 128KHz Bitrate and 48 KHz sampling rate. So the overall space used on a DVD will be identical for the same bitrate. Whether or not AC3 sounds better than MPEG1, I just don't know, but I can guarentee that the MPEG1 decoded, and then recoded to AC3 will never sound better than the original MPEG1.

If you can take a 256KB MPEG1 and recode it to 192KB AC3, and not lose much quality then perhaps AC3 is a better choice for you.

There are a number of good technical reasons why AC3 was choosen as the DVD standard, and perhaps some political ones as well. AC3 has a much better model for multi-channel audio with the ability to encode an LFE (sub woofer) along with the font and rear speakers. The model also contains instructions on how to mix down a 5.1 so that two channel devices (like VideoReDo) can play it.

[Lester Burnham]

The bit densities on MPEG1 audio and AC3 are identical. 0.0625 bytes / msec of audio at a 128KHz Bitrate and 48 KHz sampling rate. So the overall space used on a DVD will be identical for the same bitrate. Whether or not AC3 sounds better than MPEG1, I just don't know, but I can guarentee that the MPEG1 decoded, and then recoded to AC3 will never sound better than the original MPEG1.

If you can take a 256KB MPEG1 and recode it to 192KB AC3, and not lose much quality then perhaps AC3 is a better choice for you.

There are a number of good technical reasons why AC3 was choosen as the DVD standard, and perhaps some political ones as well. AC3 has a much better model for multi-channel audio with the ability to encode an LFE (sub woofer) along with the font and rear speakers. The model also contains instructions on how to mix down a 5.1 so that two channel devices (like VideoReDo) can play it.



This is sort of the core of why may formats use compressed streams, though - be it for feature / functionality - in the case of DVD audio for multichannel, and also from a space efficiency perspective.

Compressed AC3 and / or dts does tend be received well - and in fairness, you have to consider why these compressions exist. Also, I seem to recall that AC3 tracks can be up to 768kb/s and dts approaching double that.

Isn't the limit for mpeg 384?

It's always bang for buck, though, with this sort of thing - ultimate quality isn't achieved through compression - it's a case of enhanced features, and / or squeezing as much as possible on the media. But bearing in mind that I think DD and dts can use quite high bitrates.

[Grandpa Broon]

Hi all, thanks for contributing to this subject. It might be all in my mind but I assumed that the BBC transmit on Freeview in a similar manner as they do on their analogue platform (Nicam Digital) but I know that Nicam is not a digital format.

When I watch a film broadcast on my Nicam TV which contains a Dolby ProLogic signal I hear it that way through my AV system the same as VHS tapes and LaserDiscs. When I burn a DVD in AC3 recorded from my DigiTV card I get the same effect, but it may all be in my head as I was forgetting that Nicam is an analogue format.

The reason I assumed that mpeg does not do this was I recorded a music Laserdisc to DVD in mpeg format and lost the ProLogic Surround signal in the process and ended up with just stereo.

But thats only one point to my problem, why do mpeg files recorded from a TV card behave differently in authoring programs as opposed to those produced by either DV editing or by conversion from avi etc? See first post for more details.

The DigiTV mpegs are recorded with "DVD authoring Tool Compatible" format set. If they are re-encoded the problem disappears so it's possibly to do with the encoding method used by TV cards.

As I said earlier this problem is apparent in other authoring packages.

Thanks for your help
David

[Lester Burnham]

Hi all, thanks for contributing to this subject. It might be all in my mind but I assumed that the BBC transmit on Freeview in a similar manner as they do on their analogue platform (Nicam Digital) but I know that Nicam is not a digital format.

When I watch a film broadcast on my Nicam TV which contains a Dolby ProLogic signal I hear it that way through my AV system the same as VHS tapes and LaserDiscs.



That's because prologic is multiplexed within a normal stereo signal.

However, DD streams can set a flag within the DD stream to indicate that although stored as stereo, are actually surround / prologic. That is superfluous, though, to audio that isn't DD.

That doesn't mean that none DD audio can't be reproduced as prologic - the prologic decoder just looks at the stereo signal and constructs the (mono) rear effects from anything suitable within the signal.

Take a CD, play it through your AV amp, and have you AV amp output prologic - you'll usually get something out of the rears.



When I burn a DVD in AC3 recorded from my DigiTV card I get the same effect, but it may all be in my head as I was forgetting that Nicam is an analogue format.



So is surround / prologic - just something extra multiplexed in.



The reason I assumed that mpeg does not do this was I recorded a music Laserdisc to DVD in mpeg format and lost the ProLogic Surround signal in the process and ended up with just stereo.



Prologic is just stored as stereo.

As I said, there is a DD flag within the stream to automatically indicate that something is surround / prologic.



But thats only one point to my problem, why do mpeg files recorded from a TV card behave differently in authoring programs as opposed to those produced by either DV editing or by conversion from avi etc? See first post for more details.



Dunno - what sort of mpeg stream is being stored / recorded?



The DigiTV mpegs are recorded with "DVD authoring Tool Compatible" format set. If they are re-encoded the problem disappears so it's possibly to do with the encoding method used by TV cards.



Well I use a WinTV device (USB2) and for authoring, it's always considered best to use program stream, as opposed to the DVD compatible option.



As I said earlier this problem is apparent in other authoring packages.

Thanks for your help
David



Can you use program stream?

If not, consider using PVAstrumento and convert to PS.

[DanR]

If not, consider using PVAstrumento and convert to PS.The Hauppage DVD stream is a PS, with a different PS header structure. And you can use VideoReDo to convert it to the structure you want.

I'm not sure how good prolgic would be after MPEG or AC3 compression. Prologic relies upon precise phase differences between the 2 channels to simulate rear channel activities. Its quite likely the compression algorithms will havic with the phase.

[Lester Burnham]

If not, consider using PVAstrumento and convert to PS.


The Hauppage DVD stream is a PS, with a different PS header structure. And you can use VideoReDo to convert it to the structure you want.



Well for Hauppauge WinTV stuff, people in the forums have always recommended using PS rather than the DVD compatible stream option. However, personally, I use Wintvcap, so specify PS in the ini file.

But for other types of wintv cards I wasn't sure (the OP is a DigiTV user?)

I assumd he was using VideoReDo given it being posted here, but maybe the stream is something odd? He initially mentioned using ES, but then talked about transport stream and DVD compatible.

Does VideoReDo cater for all different types of streams?



I'm not sure how good prolgic would be after MPEG or AC3 compression. Prologic relies upon precise phase differences between the 2 channels to simulate rear channel activities. Its quite likely the compression algorithms will havic with the phase.



I'll have to pay more attention to captures I make from TV, then burn to DVD to see how much rear channel sound I get.

[Grandpa Broon]

The Nebula DigiTV card saves as TS which when played in WMP can give jerky motion. Selecting the option to save as DVD Authoring format does not produce this so it maybe PS. I don't have to use PVAstrumento or ProjectX like in the earlier versions of the software. The mpegs are perfect in all respects which can be edited with VRD and authored, I use Encore and burn to DVD, which then plays perfectly on my Pioneer (stand alone) DVD player.

The only problem I have is within Encore when using the preview monitor timeline to scrub to a particular timecode to insert a chapter point and then play from there. The audio plays from the chapter point ok but the video plays from where I was before I scrubbed to that point thus making the audio and video out of sync. But it is not really out of sync because if I then burnt the DVD it would be okay.

The problem is this makes inserting chapter points impossible because you don't know where you are on the timeline. But as I said earlier other people are having this problem with captured mpegs from TV cards using other authoring packages. So it must be the way some of the cards encode the mpegs.

Anyway if I don't use elementary files it's okay, so with TV editing thats what I probably do. I like to use elementary files because quite often I edit the audio to remove unwanted whats coming up next chat during the end credits. Doing it this way would mean having to re-mux the files afterwards.

It's never easy, but lots of fun.

[DanR]

Does VideoReDo cater for all different types of streams?
We can read both TS (beta version) as well as PS. Output is to PS or ES. TS output will be added in the future.

[Lester Burnham]

The Nebula DigiTV card saves as TS which when played in WMP can give jerky motion. Selecting the option to save as DVD Authoring format does not produce this so it maybe PS. I don't have to use PVAstrumento or ProjectX like in the earlier versions of the software. The mpegs are perfect in all respects which can be edited with VRD and authored, I use Encore and burn to DVD, which then plays perfectly on my Pioneer (stand alone) DVD player.

The only problem I have is within Encore when using the preview monitor timeline to scrub to a particular timecode to insert a chapter point and then play from there. The audio plays from the chapter point ok but the video plays from where I was before I scrubbed to that point thus making the audio and video out of sync.



Is this after you've edited with VideoReDo? Because it kinda sounds like PTS issues, and VideoReDo should sort that.



The problem is this makes inserting chapter points impossible because you don't know where you are on the timeline. But as I said earlier other people are having this problem with captured mpegs from TV cards using other authoring packages. So it must be the way some of the cards encode the mpegs.



Well I have read some purists pouring scorn over how some TV cards enocde mpegs ;-)



Anyway if I don't use elementary files it's okay, so with TV editing thats what I probably do. I like to use elementary files because quite often I edit the audio to remove unwanted whats coming up next chat during the end credits.



Yup I can understand that - and when I get more time to spend on it, I'll probably try and do the same.

I'd also like to use some logo busting filters, because sometimes they add these to the end of some programs. And in general, I'd like to be able to get rid of logos on many of my TV captures.



Doing it this way would mean having to re-mux the files afterwards.

It's never easy, but lots of fun.



Well there is that - I try and do as little with the files, bar editing at the moment, because I want to try and get my disks burnt robustly, and not have any qualms about lip synch. Once I get an established procedure, I'll probably try and tinker some more.

[Grandpa Broon]

Dan did you get a chance to compare the two mpeg files I uploaded to you the other week to see why the files from DigiTV act differently within Encore compared to DV encoded mpeg files.

Regards David

[DanR]

No, I haven't yet, bit I haven't forgotten about you. Will get to it this week.

[Anonymous]

MPEG (Layer 2) audio is mandatory for PAL DVDs. Its it not mandatory for NTSC DVDs, but I've yet to come across a player that won't handle it.

I have a Toshiba SD2700 and it doesn't play MPEG Audio - I convert to AC3 with better compression and good results. It doesn't take long either in Encore.