Hello! > Actually, that's not a crime. There's no requirement that MPEG audio > frames are aligned inside PES packets (i.e. a frame header immediately > follows the PES header).
Yes; I didn't state otherwise.. > How often does the "skipping" message appear? Does it happen while the > file is indexed or when it is exported? It happens whenever the file is opened (no matter whether already indexed or not) and repeats for some \approx 160 times, corresponding to the skipping of an entire TS packet until the MPA header ist found (in the next TS packet I assume). When it is exported, the problem with the timestamps shows up and there are audible "skips". > > However, also the old ffmpeg version included with dvbcut appears to > > have this "problem"; at least when the libavformat muxer is used there > > are error messages about "non-monotonous timestamp" when such packets > > are encountered. > > > > Did anyone else ever notice this? > > The "non-monotonous" message is not an indicator - the libavformat muxer > (at least the included version) uses a wrong formula to calculate the > timestamps (DTS, IIRC). Could you perhaps elaborate so the DTS computation can be fixed? Or do you mean it shouldn't use DTS at all? [but this is no priority as it isn't relevant to the issue in question] As I said, when I use the libavformat muxer there are audible skips as well. > You'd better not use it if you want correct > timestamps in the output file. Well, generally the ffmpeg DVD muxer (I have used it mostly stand-alone admittedly) has been working very, very well for me.. > Updating ffmpeg might be an option. But that would probably open a new > can of worms. The library interface is a moving target, and I don't > consider the package dependable at all. If you use the latest CVS > version, you do so at your own risk (and I recommend you don't). I know, and the risk is ok. My long-term plan is to add teletext subtitle support, however, and I have that already working in ffmpeg-current. > > I think the proper long-term solution would be to use a framer/parser > > such as the one from ffmpeg. Below is a more minimal patch to make > > sure only full audio frames can become an "item". > > That was on our wish list for the new indexer, as far as I remember. > > An "item" is always a PES packet, not an audio or video frame. Since > your patch enforces an alignment that actually need not be there, you > may end up with no audio at all. That is indeed possible, yes, but only if there are _never_ packets with an MPA header after the PES header (*). > We already had a similar problem with > Channel4 (UK) which transmits unaligned MPEG audio. Was that (*) the case there? > I'm not sure if the input file is the problem in the first place. It may > also be a bug in the version of ffmpeg you're using. Can you confirm > that the stream is malformed, No, I'm not in fact claiming the stream is malformed.. I am claiming that dvbcut passes un-framed audio data to libavcodec, and that fails -- spectacularly with ffmpeg-current but I believe it was never documented to work correctly and also silently goes wrong with the old ffmpeg version in dvbcut. > or at least provide a ~20 MB snippet of > the original TS for analysis? Will do if necessary. Thanks for your response. Regards, Wolfram. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ DVBCUT-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dvbcut-user
