Evel Posted June 3, 2009 Posted June 3, 2009 Why do some PVRs/DVDRs make a point of stating "DVB-T" tuner? What is it and how does it differ from a normal tuner? Thanks.
charlesc Posted June 3, 2009 Posted June 3, 2009 (edited) DVB-T Terrestrial DVB-C Cable DVB-S Satellite DVB-T is the digital TV transmission system that we use here in Australia, as do many other parts of the world. It is one of the above 'family' of DVB systems. There are many links that would appear with a quick search on this. These might help as a starting point:- http://www.dvb.org/about_dvb/history/ http://www.digitaltv.com.au/dvbt.html Edited June 3, 2009 by charlesc
diesel Posted June 3, 2009 Posted June 3, 2009 (edited) Why do some PVRs/DVDRs make a point of stating "DVB-T" tuner? What is it and how does it differ from a normal tuner? Thanks.A 'normal' tuner is analogue only.Have a read of the Digital Recorders Help: Stbs, Pvrs, Dvdrs, Hdd, Sd, Hd ...., NUBIE DTV info, PVR or DVDR? Problems?? .... UPDATED May 29 2009 thread. The first post is a pretty comprehensive introduction in Digital TV You will already be seeing ads for Digital "DAB" radios. the Radio spectrum has just started rolling out digital broadcasts so you will start to see raidos stating DAB on their chassis Edited June 3, 2009 by diesel
MickB...... Posted June 3, 2009 Posted June 3, 2009 DVB stands for Digital Video Broadcasting. Its a broadcast standard adopted by many countries for digital TV. It just means that the broadcast system works the same in all countries or organisations that have adopted it. DVB-T The T is for Terrestrial or normal TV, but digital not analogue. Another version is DVB-H. Not available in Australia yet but its for digital TV on your mobile phone or other portable handheld (H) device. The phone needs a DVB-H tuner to make it work.
redesp Posted June 4, 2009 Posted June 4, 2009 G'day Evel I had the same question as you. I couldn't figure out what the difference between DVB-T and HS/SD Was. I raised the question in another thread.. answers below.. hope it helps. Responce from MICK DVB-T is the standard for Digital broadcasting in Australia. A DVB-T tuner can recieve these signals, however, they come in two flavours - SD and HD. SD tuners can recieve and decode only SD signals, and HD tuners can decode HS and SD signals. My reply to MICK Makes sense to me now.. dam salesguys don't really know their ass from thier elbow somtimes... I had one guy tell me there's no such thing as DVB-t, one tell me that HD and DVB are the same and one tell me that as long as the unit was DVB compatible it will be OK. Hence the reason I ask the Q's here. So DVB-T is the transmission format (both SD and HD) and the type of tuner you have in your PVR/ DVR unit will denote it's output (even if it's can upscale the SD to HD format). DVB-t. Is how the signal is sent. if your tuner is HD it will give you a HD output. if your tuner is SD it will give you SD output (or maybe upscale)
diesel Posted June 4, 2009 Posted June 4, 2009 (edited) Responce from MICKDVB-T is the standard for Digital broadcasting in Australia. A DVB-T tuner can recieve these signals, however, they come in two flavours - SD and HD. SD tuners can recieve and decode only SD signals, and HD tuners can decode HSHD and SD signals. typoDVB-t. Is how the signal is sent.if your tuner is HD it will give you a HD output. if your tuner is SD it will give you SD output (or maybe upscale) DVB-T is the standard we use in Australia to transmit digital TV - see 2nd post by charles Digital TV in Australia is transmitted in two flavours - Standard Definition (SD - which makes up 10 of the Freeview channels) and High Definition (HD - which makes up the other 5 of the Freeview channels). Some channels are a simulcast of their SD counterparts If you have a HD tuner, you will be able to decode/watch/record HD and SD signals. SD channels will still be in SD (576i). HD channels will be in 1080i or 720p depending on the station If you have an SD only tuner, you will only be able to decode the SD signals. Upscaling will depend on your equipment and how it is connected. It has nothing to do with SD or HD transmissions Edited June 4, 2009 by diesel
prl Posted June 4, 2009 Posted June 4, 2009 ...Standard Definition (SD - which makes up 10 of the Freeview channels) and High Definition (HD - which makes up the other 5 of the Freeview channels). Some channels are a simulcast of their SD counterparts If you have a HD tuner, you will be able to decode/watch/record HD and SD signals. SD channels will still be in SD (576i). HD channels will be in 1080i or 720p depending on the station If you have an SD only tuner, you will only be able to decode the SD signals. It's not strictly the tuner that makes the difference between being able to view HD or not. The tuner's job is to take the analog signal in the channel (at the broadcast level, digital TV is analog) and turn it into a stream of bits. That stream of bits contains both the SD and HD services in that channel (e.g. for the ABC channel, it will contain all of ABC1, ABC2, ABC HD, DiG Radio and DiG Jazz). The next stage, the decoder, pulls out the part of that bit stream that contains the program you want to watch and decodes it from its compressed form into the uncompressed form that is presented on the screen. To decode HD requires a good deal more processing "grunt" than SD, and it's at this point that SD-only and HD devices differ. PVRs (for several good reasons) record by storing the program's bit stream before decoding. This means that some Topfield SD models could record HD programs, but couldn't play them back. The programs could be copied off the PVR to a PC and played back there with suitable software.
Robert E Posted June 4, 2009 Posted June 4, 2009 HD channels will be in 1080i or 720p depending on the station ... excepting the Prime (if you can call it that) Network who still often broadcast (or redirect you to) 576i on their HD LCNs. Robert - still peeved of at the Network that introduced watermarking to my FTA TV services many years ago and continues to stuff around with their broadcasting.
diesel Posted June 4, 2009 Posted June 4, 2009 Robert - still peeved of at the Network that introduced watermarking to my FTA TV services many years ago and continues to stuff around with their broadcasting. New SBS OneHD logo is very off putting...I wonder how long before Ten's OneHD take them up on the similar name???
swordfish805 Posted June 4, 2009 Posted June 4, 2009 New SBS OneHD logo is very off putting...I wonder how long before Ten's OneHD take them up on the similar name??? ...or how long before the ABC has a go at ten for copying the 1 idea (ABC1 was there first).
rjv Posted June 4, 2009 Posted June 4, 2009 It's not strictly the tuner that makes the difference between being able to view HD or not. The tuner's job is to take the analog signal in the channel (at the broadcast level, digital TV is analog) and turn it into a stream of bits. That stream of bits contains both the SD and HD services in that channel (e.g. for the ABC channel, it will contain all of ABC1, ABC2, ABC HD, DiG Radio and DiG Jazz).The next stage, the decoder, pulls out the part of that bit stream that contains the program you want to watch and decodes it from its compressed form into the uncompressed form that is presented on the screen. To decode HD requires a good deal more processing "grunt" than SD, and it's at this point that SD-only and HD devices differ. PVRs (for several good reasons) record by storing the program's bit stream before decoding. This means that some Topfield SD models could record HD programs, but couldn't play them back. The programs could be copied off the PVR to a PC and played back there with suitable software. I have noticed that my SD PVR can show the HD channel program guide but can't show the actual broadcast. It's odd that I can get the EPG though. Thx to all for the explanations
diesel Posted June 4, 2009 Posted June 4, 2009 The EPG data is transmitted in the same Mux as the SD and HD transmissions. Your EPG being able to display the HD channel information shouldn't be restricited to you having an SD only tuner Adds to the confusion I suppose for people as they can see say OneHD EPG data but can't display the channel itself
charlesc Posted June 4, 2009 Posted June 4, 2009 The tuner's job is to take the analog signal in the channel (at the broadcast level, digital TV is analog) and turn it into a stream of bits. I'd probably add another step in there, the demodulator. This is the bit that works on the analog output of the tuner, and 'recovers' the digital data stream, in essence the TS transport stream. And, in the same way that some tuners are better than others, some demodulators work more effectively to recover the data stream from an impaired signal. That stream of bits contains both the SD and HD services in that channel (e.g. for the ABC channel, it will contain all of ABC1, ABC2, ABC HD, DiG Radio and DiG Jazz). This is the 'full' transport stream, yes. The next stage, the decoder, pulls out the part of that bit stream that contains the program you want to watch and decodes it from its compressed form into the uncompressed form that is presented on the screen. Yes. PVRs (for several good reasons) record by storing the program's bit stream before decoding. This means that some Topfield SD models could record HD programs, but couldn't play them back. The programs could be copied off the PVR to a PC and played back there with suitable software. When the full transport stream is recorded, individual parts of it can later be pulled from it, yes.
prl Posted June 4, 2009 Posted June 4, 2009 I'd probably add another step in there, the demodulator. This is the bit that works on the analog output of the tuner, and 'recovers' the digital data stream, in essence the TS transport stream.And, in the same way that some tuners are better than others, some demodulators work more effectively to recover the data stream from an impaired signal. ... Absolutely correct, but I was trying to keep the detail to what was necessary to explain the behaviour that was being asked about.
charlesc Posted June 5, 2009 Posted June 5, 2009 Absolutely correct, but I was trying to keep the detail to what was necessary to explain the behaviour that was being asked about. I know, but this thread is already expanding quite a bit. And there was only one step left out...
prl Posted June 5, 2009 Posted June 5, 2009 I know, but this thread is already expanding quite a bit. And there was only one step left out...
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