Re: [Freevo-users] dvb question
El Viernes, 1 de Febrero de 2008 22:43, Adam Charrett escribió: This encoded video/audio is carried in an MPEG2 transport stream, this is used even if the video is MPEG4 encoded. Ahhh... This was the detail that I didn't know. Now it is pretty clear that while the transport doesn't change, the content can change a lot without having to change the standard. About needing more bandwidth, perhaps it is possible to split a HD channel in two or more streams. The important thing is that the answer to my question it is possible. Thx Alberto - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Freevo-users mailing list Freevo-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freevo-users
[Freevo-users] dvb question
Hi. I have a dvb related question. Not directly related to freevo, but, depending on the answer, it might be in the future. I'm doing this question here because some people might now and, who knows, depending on the country it might be important. My question is about dvb-t, the standard behind digital terrestril tv, the new tv in Europe. In every analog channel, there is a stream containing up to 4 digital channels (that is, audio+video, what you see), and perhaps some data or some more audio channels. It is an mpeg2 strean, and the cards used in computers can tune a channel, extract the stream and decode it. So, the question: What if the stream isn't in mpeg2 but in mpeg4 (for example)? I think that, at least in Spain, some tests have been done to increase quality with the same bitrate. What I want to know is if the same cards will work in this case. Will they still capture the stream and let the cpu (mplayer rocks) decode it? Or the signal will just be ignored? The modulation won't change, so the card should see the signal and, at least, the receiver should see the bitstream, but if someone knows for sure, I'd like to know. It would be great to know that even if dvb-t changes this, we won't need a new receiver. Alberto - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Freevo-users mailing list Freevo-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freevo-users
Re: [Freevo-users] dvb question
On Friday 01 February 2008 18:26, Alberto Hernando wrote: Hi. I have a dvb related question. Not directly related to freevo, but, depending on the answer, it might be in the future. I'm doing this question here because some people might now and, who knows, depending on the country it might be important. My question is about dvb-t, the standard behind digital terrestril tv, the new tv in Europe. In every analog channel, there is a stream containing up to 4 digital channels (that is, audio+video, what you see), and perhaps some data or some more audio channels. It is an mpeg2 strean, and the cards used in computers can tune a channel, extract the stream and decode it. So, the question: What if the stream isn't in mpeg2 but in mpeg4 (for example)? I think that, at least in Spain, some tests have been done to increase quality with the same bitrate. What I want to know is if the same cards will work in this case. Will they still capture the stream and let the cpu (mplayer rocks) decode it? Or the signal will just be ignored? The modulation won't change, so the card should see the signal and, at least, the receiver should see the bitstream, but if someone knows for sure, I'd like to know. It would be great to know that even if dvb-t changes this, we won't need a new receiver. Alberto - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Freevo-users mailing list Freevo-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freevo-users Hi, I don't know about all the DVB cards, but according to what I know about the mpeg2 definition, there is quite a difference between the transport stream and the elementary streams. The transport stream of DVB-S/T/C/H should always refer to the mpeg2 specification. However, the single elementary streams embedded in such a transport stream can have multiple formats, like mpeg2, mpeg4, different audio formats and even private data formats with special provider dependend coding (like e.g. the infosat epg). I.e. the mpeg4 only is about the format of the elementary stream. A (full featured?) DVB-card seems only to do the tuning into one transponder (bouquet) and (maybe) filter which elementary streams to send (by the id of the elementary stream). The decoding of these elementary streams is done by software like mplayer. At the end, I am pretty sure that mplayer can play this. On the other hand, there is HDTV (where I do not really believe that HDTV is transmitted via DVB-T). It seems that for HDTV, a higher bandwidth is used and you need special receivers. Just my 2c... Regards, Thorsten - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Freevo-users mailing list Freevo-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freevo-users
Re: [Freevo-users] dvb question
On Fri, 2008-02-01 at 18:26 +0100, Alberto Hernando wrote: Hi. I have a dvb related question. Not directly related to freevo, but, depending on the answer, it might be in the future. I'm doing this question here because some people might now and, who knows, depending on the country it might be important. My question is about dvb-t, the standard behind digital terrestril tv, the new tv in Europe. In every analog channel, there is a stream containing up to 4 digital channels (that is, audio+video, what you see), and perhaps some data or some more audio channels. It is an mpeg2 strean, and the cards used in computers can tune a channel, extract the stream and decode it. So, the question: What if the stream isn't in mpeg2 but in mpeg4 (for example)? I think that, at least in Spain, some tests have been done to increase quality with the same bitrate. What I want to know is if the same cards will work in this case. Will they still capture the stream and let the cpu (mplayer rocks) decode it? Or the signal will just be ignored? The modulation won't change, so the card should see the signal and, at least, the receiver should see the bitstream, but if someone knows for sure, I'd like to know. It would be great to know that even if dvb-t changes this, we won't need a new receiver. Alberto To answer your question Alberto, no you won't need a new card to receive the new MPEG4 channels. To be more specific, DVB-T current specifies the use of MPEG2 to encode the Video and Audio (with AC-3 also being allowed). This encoded video/audio is carried in an MPEG2 transport stream, this is used even if the video is MPEG4 encoded. The information in the MPEG2 transport streams allows the decoder to pick the right codec be that MPEG2 video or MPEG4. Of course once DVB-T2 starts to be transmitted, then you might need a new card, but it hasn't even been drafted yet. Cheers Adam - This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/ ___ Freevo-users mailing list Freevo-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freevo-users
