DVB documentation unclear/outdated
Hallo! I now have an DVB-T USB stick working and went through the mplayer documentation for DVB. I find this section of the docs very confusing and out dated. Here some suggestions: 1) What is ment by dvb output? Can ff-dvb-card (full featured dvb cards) be use with mpegpes for hardware encoding??? Or does it mean one can use ff-dvb- cards to decode any mpeg-stream by the hardware even if it is not DVB? If that's ment the term dvb output is very confusing. I'd suggest something like: "Use full featured dvb cards to do hardware decoding on mpeg2-streams other than dvb, eg. dvd vob-files" 2) The hardware decoding example differs from the first software decoding line only in the file name. Does the file extension make the difference? 3) Is mpegpes only ment for ff-dvb-cards? If so, it should be mentioned as now a days budget cards get more and more common. 4) In connection with mpegpes there is also mpeg-4 mentioned. Is that for chips which can do mpeg-4 hardware decoding? 5) It could be said in the dvb input part that an alang-option set in any configfile can lead to no sound if the language is not in the stream. 6) Last there is "realtime transcoding between MPEG-2 and MPEG-4 (partial decompression)" mentioned. It seems this is outdated. In my researches I found out that in 2002 it had been dropped off the ToDo-list. I couldn't find anything newer to that concerning mplayer/mencoder. Is it possible now? If so, how? As far as I can understand I found something about it at the TU Braunschweig. (mpeg-4 transcoding http://www.ibr.cs.tu-bs.de/users/brandt/ ) Can that be use for mplayer? Finally: If I use the keys 'h' or 'k' to change the channel when watching dvb- t mplayer changes it but then does not take any further input from the keyboard. Ctrl-C works though. Same happens when I use the menu with dvbsel to change the channel. What can I do about it? MPlayer rules! Thanks Lynx
lynx.abraxas@freenet.de wrote:
Hallo!
I now have an DVB-T USB stick working and went through the mplayer documentation for DVB. I find this section of the docs very confusing and out dated. Here some suggestions:
1) What is ment by dvb output? Can ff-dvb-card (full featured dvb cards) be use with mpegpes for hardware encoding??? Or does it mean one can use ff-dvb- cards to decode any mpeg-stream by the hardware even if it is not DVB? If that's ment the term dvb output is very confusing.
DEcoding
I'd suggest something like: "Use full featured dvb cards to do hardware decoding on mpeg2-streams other than dvb, eg. dvd vob-files"
2) The hardware decoding example differs from the first software decoding line only in the file name. Does the file extension make the difference?
no
3) Is mpegpes only ment for ff-dvb-cards?
yes
If so, it should be mentioned as now a days budget cards get more and more common.
4) In connection with mpegpes there is also mpeg-4 mentioned. Is that for chips which can do mpeg-4 hardware decoding?
none of them is supported; maybe there's an example to transcode from dvb input to mpeg4
5) It could be said in the dvb input part that an alang-option set in any configfile can lead to no sound if the language is not in the stream.
right
6) Last there is "realtime transcoding between MPEG-2 and MPEG-4 (partial decompression)" mentioned. It seems this is outdated. In my researches I found out that in 2002 it had been dropped off the ToDo-list. I couldn't find anything newer to that concerning mplayer/mencoder. Is it possible now?
it's been possible since dvb:// and demux_ts were added to mplayer
If so, how? As far as I can understand I found something about it at the TU Braunschweig. (mpeg-4 transcoding http://www.ibr.cs.tu-bs.de/users/brandt/ ) Can that be use for mplayer?
Finally: If I use the keys 'h' or 'k' to change the channel when watching dvb- t mplayer changes it but then does not take any further input from the keyboard.
??
Ctrl-C works though. Same happens when I use the menu with dvbsel to change the channel. What can I do about it?
it works here
MPlayer rules!
Thanks Lynx
Hi, On 2/9/07, Nico Sabbi <nicola_sabbi@fastwebnet.it> wrote:
lynx.abraxas@freenet.de wrote:
Hallo!
I now have an DVB-T USB stick working and went through the mplayer documentation for DVB. I find this section of the docs very confusing and out dated. Here some suggestions:
[..] Lynx, you're welcome to send a patch to update the dvb doc, based on information given by Nico (the DVB maintainer). Guillaume
Hallo Nico Sabbi! I wouldn't mind writing a patch for the DVB docs if I had the confidence to be knowleged enough to do so. On 09/02/07 23:32:18, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
2) The hardware decoding example differs from the first software decoding line only in the file name. Does the file extension make the difference?
no
In http://www.mplayerhq.hu/DOCS/HTML-single/en/MPlayer.html#dvb it says: USAGE. Hardware decoding (playing standard MPEG-1/2 files) can be done with this command: mplayer -ao mpegpes -vo mpegpes file.mpg|vob Software decoding or transcoding different formats to MPEG-1 can be achieved using a command like this: mplayer -ao mpegpes -vo mpegpes yourfile.ext How is that ment?
4) In connection with mpegpes there is also mpeg-4 mentioned. Is that for chips which can do mpeg-4 hardware decoding?
none of them is supported; maybe there's an example to transcode from dvb input to mpeg4
I don't think the examples show a way of transcoding to mpeg4 for they just have a video filter addition. Have a look for yourself.
6) Last there is "realtime transcoding between MPEG-2 and MPEG-4 (partial decompression)" mentioned. It seems this is outdated. In my researches I found out that in 2002 it had been dropped off the ToDo-list. I couldn't find anything newer to that concerning mplayer/mencoder. Is it possible now?
it's been possible since dvb:// and demux_ts were added to mplayer
Doing some research with your hint to demux_ts I wasn't able to find any examples or hints how to transcode my dvb input to a mpeg4 output-file. Could You please provide some?What programme is in charge for transcoding mplayer or mencoder? (I know there is the programme transcode as well;)) What uses demux_ts: -demuxer lavf or -demuxer mpegts?
Finally: If I use the keys 'h' or 'k' to change the channel when watching dvb- t mplayer changes it but then does not take any further input from the keyboard.
??
Doing some tests I found out that only -vo xv,svga,aa,fbdev allow me to use 'h' or 'k' to change the channel without dropping input reads. I am very fond of the vidix driver. Is it a bug that it doesn't work with cvidix nor xvidix? What original file should I use for creating a patch to the DVB-docs? Regards, Lynx
lynx.abraxas@freenet.de wrote:
In http://www.mplayerhq.hu/DOCS/HTML-single/en/MPlayer.html#dvb it says:
USAGE. Hardware decoding (playing standard MPEG-1/2 files) can be done with this command:
mplayer -ao mpegpes -vo mpegpes file.mpg|vob
Software decoding or transcoding different formats to MPEG-1 can be achieved using a command like this:
mplayer -ao mpegpes -vo mpegpes yourfile.ext
How is that ment?
now the description in video.xml is crystal-clear
4) In connection with mpegpes there is also mpeg-4 mentioned. Is that for chips which can do mpeg-4 hardware decoding?
none of them is supported; maybe there's an example to transcode from dvb input to mpeg4
I don't think the examples show a way of transcoding to mpeg4 for they just have a video filter addition. Have a look for yourself.
excerpt from video.xml_ <para> If you want to record it in a different format (re-encoding it) instead you can run a command such as <screen> mencoder -o <replaceable>r1.avi</replaceable> -ovc xvid -xvidencopts bitrate=800 \ -oac mp3lame -lameopts cbr:br=128 -pp=ci dvb://<replaceable>R1</replaceable> </screen> </para> change xvid with lavc and adjust the encoding options as you prefer to obtain mpeg4
6) Last there is "realtime transcoding between MPEG-2 and MPEG-4 (partial decompression)" mentioned. It seems this is outdated. In my researches I found out that in 2002 it had been dropped off the ToDo-list. I couldn't find anything newer to that concerning mplayer/mencoder. Is it possible now?
it's been possible since dvb:// and demux_ts were added to mplayer
Doing some research with your hint to demux_ts I wasn't able to find any examples or hints how to transcode my dvb input to a mpeg4 output-file. Could You please provide some?What programme is in charge for transcoding mplayer or mencoder? (I know there is the programme transcode as well;))
mencoder
What uses demux_ts: -demuxer lavf or -demuxer mpegts?
isn't the filename clear enough? demux_ts; anyway -demuxer lavf can be used to demux dvb streams, too
Finally: If I use the keys 'h' or 'k' to change the channel when watching dvb- t mplayer changes it but then does not take any further input from the keyboard.
??
Doing some tests I found out that only -vo xv,svga,aa,fbdev allow me to use 'h' or 'k' to change the channel without dropping input reads. I am very fond of the vidix driver. Is it a bug that it doesn't work with cvidix nor xvidix?
What original file should I use for creating a patch to the DVB-docs?
Regards, Lynx
xvidix does accept 'h', 'k' and shows the osd menu. I use it every day -- "Without a frontend, mplayer is useless" - someone in mplayer-users
On 11/02/07 12:11:14, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
How is that ment?
now the description in video.xml is crystal-clear
Yepp. Now it's understandable. Thanks.
I don't think the examples show a way of transcoding to mpeg4 for they just have a video filter addition. Have a look for yourself.
excerpt from video.xml_ <para> If you want to record it in a different format (re-encoding it) instead you can run a command such as <screen> mencoder -o <replaceable>r1.avi</replaceable> -ovc xvid -xvidencopts bitrate=800 .br > -oac mp3lame -lameopts cbr:br=128 -pp=ci dvb://<replaceable>R1</replaceable> </screen> </para>
change xvid with lavc and adjust the encoding options as you prefer to obtain mpeg4
I think there is a misunderstanding. I am using transcoding here for "transcoding between MPEG-2 and MPEG-4 (partial decompression)" without decoding to raw and then encoding to mpeg4 (as mentioned at the end of DVB- doc). If I'm not mistaken decoding to raw and then encoding is called re- encoding which is not transcoding. I'm though not sure if transrating would apply here as well since they are both mpeg but not the same video formats. In the excerpt it states re-encoding not transcoding and so it is for sure mencoder's task but not what I am looking for.
6) Last there is "realtime transcoding between MPEG-2 and MPEG-4 (partial decompression)" mentioned. It seems this is outdated. In my researches I found out that in 2002 it had been dropped off the ToDo-list. I couldn't find anything newer to that concerning mplayer/mencoder. Is it possible now?
it's been possible since dvb:// and demux_ts were added to mplayer
Doing some research with your hint to demux_ts I wasn't able to find any examples or hints how to transcode my dvb input to a mpeg4 output-file. Could You please provide some?What programme is in charge for transcoding mplayer or mencoder? (I know there is the programme transcode as well;))
mencoder
I'm referring to this email from the thread here: http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
What uses demux_ts: -demuxer lavf or -demuxer mpegts?
isn't the filename clear enough? demux_ts; anyway -demuxer lavf can be used to demux dvb streams, too
If one is new and unsure about things concerning DVB, demux_ts is confusing since mplayer -demux help yields mpegts fitting to last lines of libmpdemux/demux_ts.c but making not much sense to google hit for demux_ts http://www.arcknowledge.com/gmane.comp.video.mplayer.user.dvb/2006-10/msg000... So I'm still wondering if anyhow one can use demux_ts with DVB-input to achieve transcoding in the way I discribed above? So that I end up with an mpeg4-file without re-encoding.
Finally: If I use the keys 'h' or 'k' to change the channel when watching dvb- t mplayer changes it but then does not take any further input from the keyboard.
??
Doing some tests I found out that only -vo xv,svga,aa,fbdev allow me to use 'h' or 'k' to change the channel without dropping input reads. I am very fond of the vidix driver. Is it a bug that it doesn't work with cvidix nor xvidix?
xvidix does accept 'h', 'k' and shows the osd menu. I use it every day
Sorry, my mistake. gmplayer -vo xvidix and 'h' or 'k' make mine crash but mplayer -vo xvidix does work. Contrary mplayer -vo cvidix and 'h' or 'k' make mplayer change the channel but when showing the new channel it does not care about any key strokes any more. I think this is somehow connected to dvb:// since 'h' or 'k' work forever if I use them with v4l2 mplayer -vo cvidix tv:// -tv ... Regards, Lynx
lynx.abraxas@freenet.de wrote:
I think there is a misunderstanding. I am using transcoding here for "transcoding between MPEG-2 and MPEG-4 (partial decompression)"
there's nothing "partial" here: a full decompression takes place
without decoding to raw and then encoding to mpeg4 (as mentioned at the end of DVB- doc). If I'm not mistaken decoding to raw and then encoding is called re- encoding which is not transcoding. I'm though not sure if transrating would apply here as well since they are both mpeg but not the same video formats. In the excerpt it states re-encoding not transcoding and so it is for sure mencoder's task but not what I am looking for.
re-encoding == transcoding; in this context the only difference between the transcodings done by mplayer and mencoder is the direction of the output: to file if done by mencoder, to the dvb card if done by mplayer
I'm referring to this email from the thread here: http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
unsubstantiated science ficton
What uses demux_ts: -demuxer lavf or -demuxer mpegts?
isn't the filename clear enough? demux_ts; anyway -demuxer lavf can be used to demux dvb streams, too
If one is new and unsure about things concerning DVB, demux_ts is confusing since mplayer -demux help yields mpegts fitting to last lines of libmpdemux/demux_ts.c but making not much sense to google hit for demux_ts http://www.arcknowledge.com/gmane.comp.video.mplayer.user.dvb/2006-10/msg000...
that mail isn't about trandcoding, but simply about dumping (saving) the dvb stream to file
So I'm still wondering if anyhow one can use demux_ts with DVB-input to achieve transcoding in the way I discribed above? So that I end up with an mpeg4-file without re-encoding.
as I wrote, re-encoding/transcoding - however you call it - is still done 100% by your cpu: there's nothing done by the dvb card, not even the mpeg2 decoding (although it's possible to make the dvb card to the actual decoding and use mencoder to read the uncompressed audio and video streams from the card's output: tv://, but I would never bet on the synchrony)
xvidix does accept 'h', 'k' and shows the osd menu. I use it every day
Sorry, my mistake. gmplayer -vo xvidix and 'h' or 'k' make mine crash but mplayer -vo xvidix does work. Contrary mplayer -vo cvidix and 'h' or 'k' make mplayer change the channel but when showing the new channel it does not care about any key strokes any more.
maybe *during* channel tuning
I think this is somehow connected to dvb:// since 'h' or 'k' work forever if I use them with v4l2 mplayer -vo cvidix tv:// -tv ...
-- "Without a frontend, mplayer is useless" - someone in mplayer-users
Nico Sabbi wrote:
So I'm still wondering if anyhow one can use demux_ts with DVB-input to achieve transcoding in the way I discribed above? So that I end up with an mpeg4-file without re-encoding.
as I wrote, re-encoding/transcoding - however you call it - is still done 100% by your cpu: there's nothing done by the dvb card, not even the mpeg2 decoding (although it's possible to make the dvb card to the actual decoding and use mencoder to read the uncompressed audio and video streams from the card's output: tv://, but I would never bet on the synchrony)
a small correction here: when playing non-mpeg2 content the transcoding to mpeg2 is done entirely by the cpu, so probably your source is already in mpeg4 and you don't need to access tv:// to encode it; in any case if you want an mpeg4 output you have to transcode your source using mencoder (the decoding process done by the dvb card is still possible as I described) -- "Without a frontend, mplayer is useless" - someone in mplayer-users
On 12/02/07 00:05:17, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
I think there is a misunderstanding. I am using transcoding here for "transcoding between MPEG-2 and MPEG-4 (partial decompression)"
there's nothing "partial" here: a full decompression takes place
without decoding to raw and then encoding to mpeg4 (as mentioned at the end of DVB- doc). If I'm not mistaken decoding to raw and then encoding is called re- encoding which is not transcoding. I'm though not sure if transrating would apply here as well since they are both mpeg but not the same video formats. In the excerpt it states re-encoding not transcoding and so it is for sure mencoder's task but not what I am looking for.
re-encoding == transcoding; in this context the only difference between the transcodings done by mplayer and mencoder is the direction of the output: to file if done by mencoder, to the dvb card if done by mplayer
Why is -dumpstream and co in mplayer?
I'm referring to this email from the thread here: http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
unsubstantiated science ficton
OK, that's what I feared...
What uses demux_ts: -demuxer lavf or -demuxer mpegts?
isn't the filename clear enough? demux_ts; anyway -demuxer lavf can be used to demux dvb streams, too
If one is new and unsure about things concerning DVB, demux_ts is confusing since mplayer -demux help yields mpegts fitting to last lines of libmpdemux/demux_ts.c but making not much sense to google hit for demux_ts http://www.arcknowledge.com/gmane.comp.video.mplayer.user.dvb/2006-10/msg000...
that mail isn't about trandcoding, but simply about dumping (saving) the dvb stream to file
Yes, but demux_ts is in its title;)
So I'm still wondering if anyhow one can use demux_ts with DVB-input to achieve transcoding in the way I discribed above? So that I end up with an mpeg4-file without re-encoding.
as I wrote, re-encoding/transcoding - however you call it - is still done 100% by your cpu: there's nothing done by the dvb card, not even the mpeg2 decoding (although it's possible to make the dvb card to the actual decoding and use mencoder to read the uncompressed audio and video streams from the card's output: tv://, but I would never bet on the synchrony)
xvidix does accept 'h', 'k' and shows the osd menu. I use it every day
Sorry, my mistake. gmplayer -vo xvidix and 'h' or 'k' make mine crash but mplayer -vo xvidix does work. Contrary mplayer -vo cvidix and 'h' or 'k' make mplayer change the channel but when showing the new channel it does not care about any key strokes any more.
maybe *during* channel tuning
No, even afterwards when the programme is already displayed and whatever minutes later. Do You have any idea how I could find out what's wrong there? I don't get any errors. Nor does -v or strace give something suspicious.
I think this is somehow connected to dvb:// since 'h' or 'k' work forever if I use them with v4l2 mplayer -vo cvidix tv:// -tv ...
Thanks for all the explanations. It's much clearer now. (except for cvidix + dvb) Greetings Lynx
lynx.abraxas@freenet.de wrote:
Why is -dumpstream and co in mplayer?
to save the original stream; this feature has countless benefits ;)
I'm referring to this email from the thread here: http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
unsubstantiated science ficton
OK, that's what I feared...
(and btw, it was about using a hardware mpeg2 decoder (such as a dvb card) to decode mpeg4, the opposite of what you want)
No, even afterwards when the programme is already displayed and whatever minutes later. Do You have any idea how I could find out what's wrong there? I don't get any errors. Nor does -v or strace give something suspicious.
run mplayer -v dvb:// >& log.txt and we'll see what's wrong
On 12/02/07 00:29:34, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
Why is -dumpstream and co in mplayer?
to save the original stream; this feature has countless benefits ;)
True. So mencoder dvb:// -ovc copy -oac copy does modify the input? Or would that be the same as -dumpstream?
I'm referring to this email from the thread here: http://lists.mplayerhq.hu/pipermail/mplayer-dvb/2002-August/000668.html
unsubstantiated science ficton
OK, that's what I feared...
(and btw, it was about using a hardware mpeg2 decoder (such as a dvb card) to decode mpeg4, the opposite of what you want)
Ah, well. That's a pitty. Probably the TU BS is researching on what I want but if it is so high development it won't be free:(
No, even afterwards when the programme is already displayed and whatever minutes later. Do You have any idea how I could find out what's wrong there? I don't get any errors. Nor does -v or strace give something suspicious.
run mplayer -v dvb:// >& log.txt and we'll see what's wrong
Did it with mplayer -fs -v -vo cvidix dvb://ard &> mplayer.out to have cvidix and to see when the second channel is visible. Again pressing the h changes it but then the q for quitting appears in the tty and I have to close mplayer with Ctrl-C. mplayer.out attached. Regards, Lynx
lynx.abraxas@freenet.de wrote:
True. So mencoder dvb:// -ovc copy -oac copy does modify the input? Or would that be the same as -dumpstream?
it remultiplexes the input, so it's different from the output of -dumpstream
Ah, well. That's a pitty. Probably the TU BS is researching on what I want but if it is so high development it won't be free:(
what is it?
Did it with mplayer -fs -v -vo cvidix dvb://ard &> mplayer.out to have cvidix and to see when the second channel is visible. Again pressing the h changes it but then the q for quitting appears in the tty and I have to close mplayer with Ctrl-C. mplayer.out attached.
Regards, Lynx
I'll give a look at the output whan I have some time
On 13/02/07 00:20:19, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
Ah, well. That's a pitty. Probably the TU BS is researching on what I want but if it is so high development it won't be free:(
what is it?
A rough summary translation of http://www.ibr.cs.tu-bs.de/theses/brandt/mpeg4transcoder.html?backurl=%2Fuse... : Because re-encoding (first decoding then encoding) is very cpu intensive and therefor mostly not realtime they try to develop a technique that will give the same result without full decoding. The work is finished and there should be a c/c++ implementation as a programme and as a library. And then http://www.ibr.cs.tu-bs.de/theses/brandt/mdtranscoding.html?backurl=%2Fusers... builds on previous work: It was discovered this adjusting can be done in various domains as time, space and ditail of sharpness. The task is to code a transcoding-module to mpeg-4 that can ajust the video stream in different domains at the same time. This transcoding shouldn't be done sequential but combined to reduce cpu time. It has to be handed in again as a programme and as a module. There are more details and a chart at http://www.ibr.cs.tu-bs.de/theses/brandt/mdtranscoding/?backurl=%2Fusers%2Fb... Sadly there seems to be no English version available.
Did it with mplayer -fs -v -vo cvidix dvb://ard &> mplayer.out to have cvidix and to see when the second channel is visible. Again pressing the h changes it but then the q for quitting appears in the tty and I have to close mplayer with Ctrl-C. mplayer.out attached.
Regards, Lynx
I'll give a look at the output whan I have some time
Can I do any other debugging meanwhile? Regards, Lynx
lynx.abraxas@freenet.de wrote:
On 13/02/07 00:20:19, Nico Sabbi wrote:
I'll give a look at the output whan I have some time
Can I do any other debugging meanwhile?
Regards, Lynx
did you try xvidix? (sorry, I don't remember if I asked it) -- "Without a frontend, mplayer is useless" - someone in mplayer-users
On 19/02/07 22:39:24, Nico Sabbi wrote:
lynx.abraxas@freenet.de wrote:
On 13/02/07 00:20:19, Nico Sabbi wrote:
I'll give a look at the output whan I have some time
Can I do any other debugging meanwhile?
Regards, Lynx
did you try xvidix? (sorry, I don't remember if I asked it)
Yes, with xvidix it works fine. I would need cvidix though for an X-less machine. If it is hard to figure out what's wrong then never mind. Would be a bug though, wouldn't it? Lynx
lynx.abraxas@freenet.de wrote:
Yes, with xvidix it works fine. I would need cvidix though for an X-less machine. If it is hard to figure out what's wrong then never mind. Would be a bug though, wouldn't it?
Lynx
so it seems
participants (4)
-
Guillaume POIRIER -
lynx.abraxas＠freenet.de -
Nico Sabbi -
Nico Sabbi