<DIV>Dear Dave,</DIV>
<DIV>Thanks for the detailed input. I will check all these options again as I have tried some of these s/w earlier as well with partial success.</DIV>
<DIV>As per your advice, I have used dvbstream with all pids to record TS and then I fed this to dvbsnoop to extract teletext information but somehow dvbsnoop is outputting garbled data. However, if dvbsnoop is used directly with demux device in real-time satellite transmission, then I receive the correct teletext packets. somehow storing TS with teletxt and playing it with dvbsnoop is giving us incorrcet teletext packets. I have to see where is the problem/bug in s/w?</DIV>
<DIV>Regards</DIV>
<DIV>Rahul</DIV>
<DIV>PS: Earlier I was using SZAP with record option but this is also providing only corrupted teletext data, evenif video data look alright. I am unable to understand this descrepancy.</DIV>
<DIV><BR><BR><B><I>Dave Chapman <dave@dchapman.com></I></B> wrote:</DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Rahul Shukla wrote:<BR>> Dear Dave, Thanks for pointing out DVBSTREAM tool. I will check it<BR>> and see if it solves. Are you also aware of some software which can<BR>> convert the whole Transport stream into Program stream which can be<BR>> further authored into DVD. <BR><BR>There are various ways to do that, but I don't think a perfect solution<BR>exists if you want to keep synchronised subtitles.<BR><BR>My solution to that only works if you don't need to cut commercials out<BR>of your recording. My approach is based on the fact that transport<BR>streams consist of 188 byte packets - so if you take a valid transport<BR>stream and cut it on 188 byte boundaries, you will then generate another<BR>valid transport stream.<BR><BR>I use the "dd" command with the "bs=188" option to trim the start and<BR>end of a recording. In order to find the start point, I do something
like:<BR><BR>dd if=recording.ts bs=188 skip=100000 count=20000 of=a.ts<BR>mplayer a.ts<BR><BR>and then adjust "skip" until I get the correct starting point. This is<BR>in practice a lot easier (and quicker) than it sounds.<BR><BR>I then use either Project X or PVAStrumento (under Wine) to demux the<BR>transport stream to a set of synchronised elementary video/audio<BR>streams. I then use "mplex" from the mjpegtools project to multiplex<BR>them together.<BR><BR>Because ProjectX and PVAStrumento will always drop the first and last<BR>incomplete "GOP" from the stream (a GOP is typically about half a<BR>second), then you don't have to be very accurate with the "dd" parameters.<BR><BR>I then use my dvbsubs tools to extract the subtitles and convert them<BR>into bitmaps, followed by "spumux" from dvdauthor to multiplex the<BR>subtitles into the program stream generated by mplex.<BR><BR>Finally, I use dvdauthor to author a DVD.<BR><BR>This is not a very elegant method, but it does work
reliably.<BR><BR>> Another point is that I am interested in<BR>> DVB-Teletext (VBI) storage and I guess DVB-subtitles are subset of<BR>> DVB-VBI standard, so I hope dvbtools/dvbstream can address that issue<BR>> without any problem. Thanks again Rahul<BR><BR>There are two types of DVB subtitles - "real" DVB subtitles, which are<BR>broadcast as bitmaps, and "teletext" subtitles, which as you have<BR>guessed, are just a subset of the old VBI teletext standard.<BR><BR>In my dvbtools, you will also find an old program called "dvbtext" -<BR>this decodes teletext packets encapsulated in a DVB transport stream.<BR>It shares some code with Ralph Metzler's "vbidecode" program which you<BR>may have used in the past if decoding subtitles from a BTTV analogue TV<BR>card.<BR><BR>You should also look at my "dvbtune" - especially the "-i" option which<BR>is useful for identifying subtitle PIDs and languages, and various other<BR>information about a DVB transport
stream.<BR><BR>Dave.<BR><BR>_______________________________________________<BR>MPlayer-dvb mailing list<BR>MPlayer-dvb@mplayerhq.hu<BR>http://mplayerhq.hu/mailman/listinfo/mplayer-dvb<BR></BLOCKQUOTE><BR><BR>Rahul Shukla<br>Researcher<br>HP Labs, India<p>
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