I wish there was elementary stream support

ronnylov · Post by **ronnylov** » Thu Mar 16, 2006 3:56 pm

I make recordings from my Technotrend DVB-C Premium card in a format called PVA which is the native format for this card. The PVA format is some kind of container for MPEG-2 video and audio. This card does not support ts format but it can output to mpg format but the generated mpg files are buggy and the PVA format works best.

When recording DVB there is often errors in the streams which can be corrected by PVAStrumento or ProjectX. These programs will automatically cut out the parts of video and audio that contains errors and resynch the video and audio to get perfectly audio sync but the output is normally demuxed files in m2v and mp2 format. It is also possible to output to mpg format but for a number of reasons I don't want to do that.

Usually I manually remove the commersials with MPEG2Schnitt and then I use a DVD authoring software that accepts elementary streams as input (demuxed files) so there is no need to use anything else than elementary streams. MPEG2Schnitt does the editing with elementary streams as both input and output and this suits me nice. Now I have noticed that ComSkip and ComClean4 supports MPEG2Schnitt editing so that is very nice.

But I don't like to convert the elementary streams to a mpg file in the Comskip step, it needs more disk space and I would have to delete the mpg file again after commersial detection because I use the elementary streams from ProjectX as input in MPEG2Schnitt. I noticed that ComClean4 first demuxes the mpg to elementary streams and then remux it again to mpg. Those steps are not necessary if I can input my elementary streams directly and then directly use the elementary streams output from MPEG2Schnitt.

So that's a long explanation why I think it would be useful to have a commersial detector and remover that works with elementary streams all the way. This is my suggestion for improvement of ComSkip. I don't need an input in PVA because the files need to be fixed with ProjectX or PVAStrumento before the commersial detection is done. I think most TS files probably also would need to be fixed with projectX so I guess the people that record to TS format probably also would like this feature when recording digital TV with commersials.

a_a · Post by **a_a** » Fri Mar 17, 2006 3:38 am

Motion seconded. I would love this too.

Currently, I demux using ProjectX to remove errors then remux to run through Comskip and then use Cuttermaran on the original elementary streams. The remuxed mpg is only used for Comskip and then thrown away which is really just a waste of time and disk space.

If Comskip can process the elementary streams directly we can avoid this.

If this can be done, how hard it would be to add AC3 processing as an option?

Adrian.

Post by **erik** » Fri Mar 17, 2006 1:06 pm

If being able to process elementary streams would imply that you can not use comskip in live_tv mode would that be OK?

AC3 should be possible (given enough time......)

ronnylov · Post by **ronnylov** » Fri Mar 17, 2006 2:28 pm

erik wrote:If being able to process elementary streams would imply that you can not use comskip in live_tv mode would that be OK?

AC3 should be possible (given enough time......)

If live_tv mode means that you pause the recording during the commersials instead of removing them afterwards then I think it would be OK with me because I never use comskip other than on finnished recordings. But I guess other people may use it in live mode?

Maybe a special version can be made for elementary streams in postprocessing mode?

Post by **erik** » Fri Mar 17, 2006 2:58 pm

Live_tv means that comskip is detecting commercials while the recording is being done, so you can use the comskip output during timeshifting to skip over commercials when they occur in the timeshift buffer.
Not being able to do live_tv means you can only run comskip on a finished recording.
What you do with the output of comskip, jump over a commercial during playback or remove the commercial from the recording, is independend of when you have generated the output

So processing elementary streams in postprocessing mode will not be a special version but ES input will not work during timeshifting.

ronnylov · Post by **ronnylov** » Fri Mar 17, 2006 4:57 pm

OK, well this seems fine. Elementary stream support is probably not very useful anyway when pause live recordings because I don't think live recordings output elementary streams very often.

I got another idea. I take back what I said earlier that I have no use of PVA format support. I have noticed that in ProjectX there is an option to remove the commersials manually and the cut pints are set before the demuxing and fixing is done. So my new idea is to add PVA format support to comskip and then use the output from comskip as input to ProjectX. This way only the commersial free parts will be fixed and joined by ProjectX. Very nice to have commersial removing, fixing and demuxing done in the same step with ProjectX!

I don't know if or how projectX can import cut points but then PVA support and also TS support (which can be used as input in ProjectX too) would be nice. By the way I think ProjectX also supports mpg as input format so ProjectX could be another new output format in Comskip!

The PVA file format is described in this document:
http://www.dvbmagic.de/download/datashe ... mat_v1.pdf

Post by **erik** » Fri Mar 17, 2006 6:07 pm

Faulty mpeg stream will cause difficulties for Comskip I don't mind receiving a repaired ES

uryan · Post by **uryan** » Sat May 05, 2007 12:57 am

Hi Erik,
Just wondering if there were still any plans to support ES? Currently all my workflows require a muxing step just to pass through Comskip.
Cheers.

Post by **erik** » Mon May 07, 2007 5:53 pm

Comskip need both audio and video in a well synced way. (frame accurate)
I do not think I am going to add ES input with video and audio in two separate ES files.