Record multiple channels from one multiplex

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This is a feature, referred to commonly as MultiRec and included with MythTV 0.21, which enables more than one channel to be recorded per tuner as long as the channels being recorded are being transmitted on the same DVB digital multiplex. It does not apply to analog tuners, and whether it applies to QAM digital cable depends somewhat on your carrier and your hardware.

Background

DVB digital television transmissions are multiplexed Transport Streams containing several data streams (video, audio, epg, eit, ...) identified by PIDs. When you select a TV/Radio program or data service (like EPG, Teletext, IPv4, ...) the necessary PIDs are remuxed into a new data stream which can be handled by your application. In case of a media player one video PID and one or several audio PIDs are muxed into a TS- or PES-container (there can also be timing information like PCR).

The DVB-standard specifies the MPEG2 codec for video and audio. Alternatively AC3 can be used for audio.

Because of the high bandwidth of DVB multiplexes (up to 90 MBit/s) there is usually more than one TV- or radio-program in a multiplex. In contrast to the Windows BDA driver, the LinuxDVB kernel driver can also deliver the complete Transport Stream of a multiplex.

By remuxing the TS into more than one new stream other TV applications like VDR can record several TV programs in a DVB multiplex at the same time using only one tuner for the multiplex.

Multiplex recording also allows overlapping of sequential recordings of the same program. That avoids the annoying problem with the end of a broadcast being in the next recording or the beginning of a broadcast being at the end of a previous recording, as is lately popular with syndicated reruns of programs like Scrubs and ER.

Sponsorship

Open Source Partners in Finland collected sponsorships for this development, with developers involved.

Use cases

This section originally existed to define some common things you might want to use MultiRec to do, and should be rewritten by someone familiar with the code to describe how closely these targets were hit.

Simple cases

  • User schedules recording of two programmes on different channels that share a multiplex (e.g., BBC1 and BBC2). Only one tuner should be used to record.
  • User has MythTV set up to always start recording five minutes before and after the scheduled time. User schedules recording of two back-to-back programmes on the same channel, or on different channels carried on the same transport. Only one tuner should be used to record both, despite the overlap.

Complex cases

A lot of the complexity in this change comes not from the recording code but from the scheduling. Define some edge cases to provoke discussion.

  • User has three recordings defined that will all be transmitted on one multiplex at the same time, each programme given a priority of "5". Another recording at the same time has a priority of "10" on another multiplex. With only one tuner, which programmes get recorded?
  • User has two tuners, one high priority, one low. Two programs at priority 0 are transmitted on the same transport, while one on a different transport has priority 10. Which gets the high priority tuner, and which the low priority one?
  • User has two tuners, one high priority DVB tuner, one low priority analog tuner. Two programs at priority 0 are transmitted on the same transport, while one on a different transport has priority 10. Do we give the high priority DVB tuner to the two low priority shows and put up with analog reception for the high priority show, or do we use the DVB tuner for the high priority show, and miss recording one of the lower priority shows?
  • User has two tuners, one low priority DVB tuner, one high priority analog tuner. One programs at priority 0 is on simultaneously with two priority 10 programs transmitted on the same transport. Do we give the low priority DVB tuner to the two high priority shows, or put one on the high priority analog tuner and miss the lower priority show? This may be a bit artificial, since a DVB tuner will usually have higher priority than an analog one.
  • All these same issues arise for back-to-back recordings on the same transport that are made to overlap due to start early/end late.

Setup Tuners / Capture Cards

Tuner priorities aside, when selecting a tuner for a recording, the backend will choose the first tuner defined sequentially by the MythTV setup program. As such, it is often preferred to delete all capture cards and recreate them from scratch, than to delete cards individually.

For proper setup with multi-channel-recording, or multirec, tuners should be configured in order, and the number of simultaneous recordings set all at once. This is set with the number of recordings setting in the advanced options in card configuration. Default is two, and maximum is five. When the recorder selects a tuner, it will cycle through sequentially until it finds a virtual tuner capable of receiving that channel. Proper configuration in this manner means it will properly use an in use tuner on the multiplex, before falling back to an unused tuner.

The consequence of this is that live TV can use any channel, and thus will pick the first available virtual tuner, even if locked to a multiplex. The only way to leave this multiplex is to manually switch to a different card or different source. The alternative is to go back through after adding tuners, and add one more virtual tuner for each physical one. Then set the frontend to avoid conflicts in playback settings. This will have the frontend select inputs from the back of the list, so if no recordings are currently active, each live tv session will get its own physical tuner. Be aware of the implications to scheduling conflicts this may cause.

Countries with multiplexed DVB/ATSC transmissions

Africa

Antarctica

Asia

Oceania

New Zealand

The freeview service transmits via the Optus D1 satellite and via UHF.

DTH Satellite Service

At present New Zealand has two Freeview (FTA) DVB-S transponders on Optus D1. Sky (pay tv provider) also broadcasts TV One and TV 2 unencrypted on one of their transponders. The DVB-S Transponders have enough room for upto 9 TV Channels each.

DVB-S 12483H DVB-S 12456H
TV One TV3
TV 2 C4
Maori TV Stratos
TVNZ 6 Parliament TV
TVNZ 7 Cue
TVNZ Sport Extra Reserved
Reserved Reserved
Reserved Radio NZ National
Reserved Radio NZ Concert

DTT Terrestrial Service

From April 2008 we a terrestrial DVB-T based service will start with 3 H.264 multiplexes with a mix of HD and SD content.

TVNZ Mux MediaWorks Mux Kordia Mux
TV One HD TV3 HD Maori TV
TV 2 HD C4 Parliament TV
TVNZ 6 Central TV
TVNZ 7
TVNZ Sport Extra
Radio NZ National
Radio NZ Concert

Australia

  • ABC Multiplex (ABC, ABC2/ABC4, ABC3 and ABC News 24, radio)
  • SBS Multiplex (SBS, SBS2, SBSHD, radio)
  • Seven Multiplex (Seven (or Prime), 7Two, 7Maaaaaate)
  • Ten Multiplex (Ten (or Southern Cross), Eleven, OneHD)
  • Nine Multiplex (Nine (or Win), GO!, Gem)

Analogue TV has been shut down in regional Victoria since May 2011.

Europe

  • Astra 19.2° and EutelSat 13.0° DVB-S (up to 20 radio or 8 TV programs per transponder/multiplex)

Belgium

9 Multiplexes (on In.Di wich is DVB-C- www.indi.be - Antwerp Region). Channels sorted: (TV) + (Radio)

  • Multiplex A (Canvas/Ketnet, 2Be, VijfTV, info INDI SD, Jim MTV/Nick) + (Radio BemBem)
  • Multiplex B (Life!TV, S.Televisie, Actua TV, BBC One, BBC Two, BBC Prime) + (BBC Radio 1, 2, 3, World)
  • Multiplex C (TF1, France2, France3, France5) + (FR Musique, Culture, Inter)
  • Multiplex D (ARD, ZDF, WDR, ProSieben) + (1Live, WDR2, WDR3, WDR4, WDR5)
  • Multiplex E (Nederland1, Nederland2, Nederland3) + (Ned Radio 2, Ned Radio 4)
  • Multiplex F (TMF Party)
  • Multiplex G (La Une, La Deux, RTL-TVI)
  • Multiplex H (VTM, VT4, één, VTM HD) + (Q Music)
  • Multiplex I (Cartoon net, TCM, EXQI, Vitaya)

all tested with concurrent recording. Extra info: www.bramkortleven.be

Czech republic

4 Multiplexes (on terrestrial, updated to 15.12.2008).

  • Multiplex 1 (CT1, CT2, CT24, CT4 Sport) + (7 radios of Cesky Rozhlas)
  • Multiplex 2 (Nova, Nova Cinema, Prima) planned: (Prima klub, TV Barrandov)
  • Multiplex 3 (Z1, Ocko, Public TV, Noe) + (radio Proglas)
  • Multiplex 4 (CT1 HD, Nova HD)

Denmark

1 Multiplex, - more will come.

Current multiplex has: DR1, DR2, Tegnsprog and TV2. As of February not all of the country are covered. Se http://www.digi-tv.dk

Finland

  • All TV stations on DVB-C/-T (up to 6 TV channels per multiplex)

4 Multiplexes (on terrestrial). Muxes A and B cover 99,9 % of country. Mux C covers 78 % - 85,4 %. Mux E is reserved for pay-TV is also operational but not covering whole country.

Multiple multiplexes on cable, depending on providing company.

TTV[1] is Finland's 2nd biggest cable tv provider with 12 multiplexes[2]. 6-10 channels per multiplex and most of the users use only 2 of them -> More than 10 free channels. Even getting 2 channels with one tuners would be HUGE improvement.

Analog TV has been switched off since 31th of August 2007 in Finland...

Germany

  • All TV stations on DVB-C/-T (4 TV programs per VHF/UHF multiplex)
  • For DVB-T see senderliste.pdf

UK

DVB-T ("Freeview")

The UK is made up of 6 multiplexes. As you can see below, with only 6 tuners you could have quite an incredible MythTV recording platform.

Mux 1 Mux 2 Mux A Mux B Mux C Mux D
BBC ONE ITV1 or (STV or UTV) Nuts TV 301 E4+1 Film4
BBC TWO ITV2 bid tv 302 / Community Sky News Ideal World
BBC THREE / CBBC ITV3 Five 305 Sky Sports News ITV2+1
BBC NEWS 24 CITV Five Life BBC FOUR / CBeebies Sky Three The HITS
Channel 4 Five US BBC News Multiscreen Dave / smileTV TMF
E4 price-drop tv BBC Parliment UKTV History / Virgin1
More 4 QVC
Quiz Call Teachers' TV
Channel4+1
ITV4

In addition, there are a large number of radio stations.

The full list can be found here: [3]

As the UK is currently in transition to all DVB-T (completed in 2012) an up to date status of Mux's and Channels can be found here: [4].

DVB-S ("Freesat")

Incomplete.png Incomplete, needs to be expanded. Please help to fill the gaps or discuss the issue on the talk page

A growing selection of FTA channels is also available for UK Television via satellite. These channels are likewise multiplexed.

The 'interesting' FreeSat TV channels that can be received with a DVB-S card (ie no Sky subscription required) and are thus available for multiplex recording:

Note especially the BBC HD and ITV HD

Astra and Eurobird Constellation at 28.2°E

tp 41 ITV 2+1 ITV 1
tp 42 FILM4 FILM4+1
tp 44 ITV 1 ITV 2 CITV ITV 4 Men & Motors
tp 45 BBC One BBC Two BBC News24 BBC Four CBBC CBeebies BBC Three
tp 47 BBC One BBC Two BBC Radio
tp 50 BBC One BBC HD
tp 54 Channel TV STV ITV 3
tp 14 Zee Music UK
tp 26 Sky News UK Sky News Ireland

Netherlands

  • TV stations on the Digitenne network are in DVB-T (multiple TV programs per multiplex, all FTA public channels on one multiplex)

E.g.: # scandvb -c
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
0x0000 0x044d: pmt_pid 0x1b62 Digitenne -- Nederland 1 (running)
0x0000 0x044e: pmt_pid 0x1b6c Digitenne -- Nederland 2 (running)
0x0000 0x044f: pmt_pid 0x1b76 Digitenne -- Nederland 3 (running)
0x0000 0x0450: pmt_pid 0x1b80 Digitenne -- TV Rijnmond (running)
0x0000 0x0457: pmt_pid 0x1bc6 Digitenne -- Radio Rijnmond (running)
0x0000 0x0458: pmt_pid 0x1bd0 Digitenne -- Radio 1 (running)
0x0000 0x0459: pmt_pid 0x1bda Digitenne -- Radio 2 (running)
0x0000 0x045a: pmt_pid 0x1be4 Digitenne -- 3FM (running)
0x0000 0x045b: pmt_pid 0x1bee Digitenne -- Radio 4 (running)
0x0000 0x045c: pmt_pid 0x1bf8 Digitenne -- Radio 5 (running)
0x0000 0x045d: pmt_pid 0x1c02 Digitenne -- Radio 6 (running)
0x0000 0x045e: pmt_pid 0x1c0c Digitenne -- Concertzender Classic (running)
0x0000 0x045f: pmt_pid 0x1c16 Digitenne -- FunX (running)
dumping lists (13 services)
Nederland 1 (0x044d) 01: PCR == V V 0x1b63 A 0x1b64 TT 0x1b65
Nederland 2 (0x044e) 01: PCR == V V 0x1b6d A 0x1b6e TT 0x1b6f
Nederland 3 (0x044f) 01: PCR == V V 0x1b77 A 0x1b78 TT 0x1b79
TV Rijnmond (0x0450) 01: PCR == V V 0x1b81 A 0x1b82 TT 0x1b83
Radio Rijnmond (0x0457) 02: PCR == A A 0x1bc8
Radio 1 (0x0458) 02: PCR == A A 0x1bd2
Radio 2 (0x0459) 02: PCR == A A 0x1bdc
3FM (0x045a) 02: PCR == A A 0x1be6
Radio 4 (0x045b) 02: PCR == A A 0x1bf0
Radio 5 (0x045c) 02: PCR == A A 0x1bfa
Radio 6 (0x045d) 02: PCR == A A 0x1c04
Concertzender Classic (0x045e) 02: PCR == A A 0x1c0e
FunX (0x045f) 02: PCR == A A 0x1c18

All of Dutch national public TV and radio in one multiplex!
See http://nl.wikipedia.org/wiki/Digitenne for details and information (in Dutch)

Norway

DVB-C from GET in Oslo (needs to be verified):

TV5		241000000
Euronews	241000000
DR 1		241000000
Voice TV	241000000
TV2 Nyhetskan	241000000
Cartoon Network	241000000
Get Infokanal	241000000
NRK1 Tegnsprak	241000000

NRK1		272000000
NRK2		272000000
TV2		272000000
TVNORGE		272000000
TV3		272000000

NRK Stortinget	280000000
NRK Super	280000000
NRK Gull	280000000
Svensk TV2	280000000
Viasat 4	280000000
SportN		280000000
TV2 Zebra	280000000
FEM		280000000

NRK P2		290000000
NRK Petre	290000000
NRK Alltid klas	290000000
Radio Norge	290000000
P4		290000000
Classical Calm	290000000
Rock Anthems	290000000
Dinner Party	290000000
Bass & Beats	290000000
Soul Classics	290000000
Strictly 60s	290000000
Jazz Classics	290000000
Under a Groove	290000000
Cocktail Lounge	290000000
Just Chillout	290000000
Got The Blues	290000000
Classical Grea	290000000
Cool Jazz	290000000
All Day Party	290000000
Hits (Germany)	290000000
Hits (Spain)	290000000
Hits (France)	290000000
Hits (Nordic)	290000000
Hits (Italy)	290000000
National Geogrc	290000000
Travel	 	290000000
Viasat Nat&Crim	290000000

Jetix		306000000
TCM		306000000
CNBC		306000000
God TV		306000000
TV Romerike 24	306000000
BBC Prime	306000000

Scand Sat Radio	314000000
Zone Club	314000000
Extreme Sports	314000000
Animal Planet	314000000
Viasat History	314000000
France 24 Eng	314000000

VH1	  	346000000

NRK Sami Radio	354000000
NRK Folkemusikk	354000000
Disc Science	354000000
Discovery World	354000000
Disc Travel&Liv	354000000
Nat Geo Wild	354000000
Playhouse Disn	354000000

BBC Food	362000000
Eurosport 2	362000000
Toon Disney	362000000
Zone Reality	362000000
Silver		362000000
Showtime	362000000
Viasat Explorer	362000000

Al Jazeera Int	370000000
TV Follo	370000000
Svensk TV4	370000000
Star!		370000000
Bloomberg	370000000

Visjon Norge	378000000
Nickelodeon	378000000
Hallmark	378000000

Sky News	386000000
Motors TV	386000000

France

Mux R1 France 2 France 3 France 4 France 5 ARTE La Chaîne Parlementaire
Mux R2 Direct 8 Gulli Europe 2 TV i>TELE BFM TV TMC
Mux R3 Canal + Canal J Planète Canal + Sport Canal + Cinéma
Mux R4 M6 W9 NT1 Paris Première TF6 AB1
Mux R5 unused unused unused unused unused unused
Mux R6 TF1 NRJ 12 TPS Star Eurosport LCI

Sweden

DVB-T and DVB-C.

There are 6 public DVB-T multiplexes. 1 - 5 covers 98% of the population, Multiplex 6 covers Stockholm at the moment. This is about 30 channels, both encrypted and unencrypted. There are also ongoing work to ensure that the Swedish population in Finland will continue to receive digital transmissions after the analog transmissions have stopped. Channels are transmitted in mpeg2 but as new channels start to broadcast mpeg4 will be used for those (2008). In 5 - 15 years, all channels should broadcast in mpeg4. Both SDTV and HDTV.

Read more at Teracom.

Some of the DVB-T channels:

Mux 1 Mux 2 Mux 3 Mux 4 Mux 5 Mux 6
SVT2 TV4 Fakta TV8 VH1 TCM TV Finland
Barnkanalen TV4 Film Kanal 5 MTV Nordic SILVER SVT HD (mpeg4)
SVT1 TV6 Canal 7 Kanal 9 BBC World
SVT24 CNN Canal+ First Star! TV7
ABC TV4 Stockholm Canal+ Hits Eurosport BBC Prime
SVT Extra TV4 Plus Disney Channel The Voice Discovery T&L
Kunskapskanalen TV400 TV3 Animal Planet Axess 25
SVT2 Tal txt Canal+ Sport1 Discovery TV4 Sport
SVT1 Tal txt ztv.se
SVT2 Nickelodeon

This is the channels that one of the big transmitters in Stockholm/Nacka broadcast.

Croatia

DVB-T

1 Multiplex ( HTV 1, HTV 2, Nova TV & RTLTelevizija)

Spain

  • All TV stations on DVB-T (Maximum of 4 TV programs per VHF/UHF multiplex. Radio stations do not count for the maximum).

Switzerland

DVB-T

1 multiplex with all channels (different channels per language region (see: http://broadcast.ch/data_program_dvbt.aspx)):

  • In German & Rhaeto-Romanic speaking part : SF1, SF2, SFINFO, TSR1, TSI1
  • In French speaking part : TSR1, TSR2, SF1, TSI1
  • In Italian speaking part : TSI1, TSI2, TSR1, SF1

At the country-border you might be able to receive neighbouring countries' DVB-T signals (In Basel with a (boosted) rooftop antenna you can additionally pick up: ARD, ZDF, 3SAT, EinsPlus, ARTE, ZDF-Infokanal, HR, Phoenix, SWR, WDR, KIKA, BR (all together on 3 multiplexes (4 channels each).

Ireland

No official DVB-T broadcasts, but there is a trial signal which is made up of 4 MUXes and is available to approx. 30% of the population in the East and North-East of the country. MUX 1 is FTA, while MUX2,3 and 4 are scrambled. Permanent services are due to start in 2008

Mux 1 RTE 1 RTE 2 TV 3 TG 4

North America

Digital cable transmissions are multiplexed. The standard encoding appears to be QAM-256 for unencrypted channels. Usually there are also lots of audio only channels multiplexed into the stream, so each frequency can have a number of streams. Maximum for one frequency with Rogers cable in the Toronto area appears to be 14 streams on one frequency...a mixture of unencrypted video+audio, audio and encrypted HD.

Rogers has a total of 424 streams!

An example dvbscan output:

Unique name:frequency:modulation: video id: audio id: serviceid (pid)

#dumping lists (424 services)
[076e]:513000000:QAM_256:26:27:1902
[0773]:513000000:QAM_256:29:30:1907
[0774]:513000000:QAM_256:18:19:1908
[0776]:513000000:QAM_256:32:33:1910
[0775]:513000000:QAM_256:37:40:1909
[0778]:513000000:QAM_256:51:52:1912
[0779]:513000000:QAM_256:53:56:1913
[07b3]:519000000:QAM_256:21:24:1971
[07b5]:519000000:QAM_256:41:42:1973
[07b6]:519000000:QAM_256:43:44:1974
[07b7]:519000000:QAM_256:46:47:1975
[07b2]:519000000:QAM_256:49:50:1970


South America