On Mon, Aug 3, 2009 at 1:53 PM, Patrick Boettcher<patrick.boettcher@xxxxxxx> wrote: > Hi all, > > I'd like to request some comments about the extension of the DVB-API 5 to > support ISDB-T and ISDB-Tsb. Some stubs in frontend.h and friends have been > there since the beginning and now it's time to have real user-space support > for that standard. > > I hope that we can finish the discussion of this RFC before the merge window > of 2.6.32, so that it can be included then. > > The current version of the patches can be found here: > > http://linuxtv.org/hg/~pb/v4l-dvb/rev/eabb8cfcf32a > > Changelog: > This patch increments the DVB-API to version 5.1 in order to reflect the > addition of ISDB-T and ISDB-Tsb on Linux' DVB-API. > > Changes in detail: > - added a small document to describe how to use the API to tune to an ISDB-T > or ISDB-Tsb channel > - added necessary fields to dtv_frontend_cache > - added a smarter clear-cache function which resets all fields of the > dtv_frontend_cache > - added a TRANSMISSION_MODE_4K to fe_transmit_mode_t > > I also added a document trying to descibe in short all the needed parameters > (DTV_CMDs) for ISDB-T(sb) and how to use them. I'm inlining this document, > as it is the base for the RFC as well: > > (Disclaimer: ISDB-T and ISDB-Tsb is relative complex from the parameters > point of view compared to DVB-T and for me the standard-document was not > making things very easy for me as a software-writer. Please don't blame me > for so many additions) > > ----------------- > This document describes shortly what are the possible parameters in > the Linux DVB-API called "S2API" in order to tune an ISDB-T/ISDB-Tsb > demodulator: > > This ISDB-T/ISDB-Tsb API extension should reflect all information > needed to tune any ISDB-T/ISDB-Tsb hardware. Of course it is possible > that some very sophisticated devices won't need certain parameters to > tune. > > The information given here should help application writers to know how > to handle ISDB-T and ISDB-Tsb hardware using the Linux DVB-API. > > The details given here about ISDB-T and ISDB-Tsb are just enough to > basically > show the dependencies between the needed parameter values, but surely some > information is left out. For more detailed information see the standard > document: > ARIB STD-B31 - "Transmission System for Digital Terrestrial Television > Broadcasting". > > In order to read this document one has to know about the channel > structure in ISDB-T and ISDB-Tsb. I.e. it has to be known to the > reader that an ISDB-T channel consists of 13 segments, that it can > have up to 3 layer sharing those segments, and so on. > > Parameters used by ISDB-T and ISDB-Tsb. > > Existing parameters > =================== > > a) DTV_BANDCOUNT_HZ > > Help the front-end, for example, to set up base-band-filters. > > Possible values: > > For ISDB-T it should be always 6000000Hz (6MHz) > For ISDB-Tsb it can vary depending on the number of connected segments > > b) DTV_DELIVERY_SYSTEM > > Possible values: SYS_ISDBT > > c) DTV_TRANSMISSION_MODE > > ISDB-T supports three carrier/symbol-size: 8K, 4K, 2K. It is called > 'mode' in the standard: Mode 1 is 2K, mode 2 is 4K, mode 3 is 8K > > Possible values: TRANSMISSION_MODE_2K, TRANSMISSION_MODE_8K, > TRANSMISSION_MODE_AUTO, TRANSMISSION_MODE_4K > > If DTV_TRANSMISSION_MODE is set the TRANSMISSION_MODE_AUTO the > hardware will try to find the correct FFT-size (if capable) and use > the TMCC to fill in the missing parameters. > > TRANSMISSION_MODE_4K is added at the same time as the other new parameters. > > d) DTV_GUARD_INTERVAL > > Possible values: GUARD_INTERVAL_1_32, GUARD_INTERVAL_1_16, > GUARD_INTERVAL_1_8, > GUARD_INTERVAL_1_4, GUARD_INTERVAL_AUTO > > If DTV_GUARD_INTERVAL is set the GUARD_INTERVAL_AUTO the hardware will > try to find the correct guard interval (if capable) and use the TMCC to fill > in the missing parameters. > > New parameters > ============== > > 1. DTV_ISDBT_PARTIAL_RECEPTION (1b) > > If DTV_ISDBT_SOUND_BROADCASTING is '0' this bit-field represents whether > the channel is in partial reception mode or not. > > If '1' DTV_ISDBT_LAYERA_* values are assigned to the center segment and > DTV_ISDBT_LAYERA_SEGMENT_COUNT has to be '1'. > > If in addition DTV_ISDBT_SOUND_BROADCASTING is '1' > DTV_ISDBT_PARTIAL_RECEPTION represents whether this ISDB-Tsb channel > is consisting of one segment and layer or three segments and two layers. > > Possible values: 0, 1, -1 (AUTO) > > 2. DTV_ISDBT_SOUND_BROADCASTING (1b) > > This field represents whether the other DTV_ISDBT_*-parameters are > referring to an ISDB-T and an ISDB-Tsb channel. (See also > DTV_ISDBT_PARTIAL_RECEPTION). > > Possible values: 0, 1, -1 (AUTO) > > 3. DTV_ISDBT_SB_SUBCHANNEL_ID > > This field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'. > > (Note of the author: This might not be the correct description of the > SUBCHANNEL-ID in all details, but it is my understanding of the technical > background needed to program a device) > > An ISDB-Tsb channel (1 or 3 segments) can be broadcasted alone or in a > set of connected ISDB-Tsb channels. In this set of channels every > channel can be received independently. The number of connected > ISDB-Tsb segment can vary, e.g. depending on the frequency spectrum > bandwidth available. > > Example: Assume 8 ISDB-Tsb connected segments are broadcasted. The > broadcaster has several possibilities to put those channels in the > air: Assuming a normal 13-segment ISDB-T spectrum he can align the 8 > segments from position 1-8 to 5-13 or anything in between. > > The underlying layer of segments are subchannels: each segment is > consisting of several subchannels with a predefined IDs. A sub-channel > is used to help the demodulator to synchronize on the channel. > > An ISDB-T channel is always centered over all sub-channels. As for > the example above, in ISDB-Tsb it is no longer as simple as that. > > The DTV_ISDBT_SB_SUBCHANNEL_ID parameter is used to give the > sub-channel ID of the segment to be demodulated. > > Possible values: 0 .. 41, -1 (AUTO) > > 4. DTV_ISDBT_SB_SEGMENT_IDX > > This field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'. > > DTV_ISDBT_SB_SEGMENT_IDX gives the index of the segment to be > demodulated for an ISDB-Tsb channel where several of them are > transmitted in the connected manner. > > Possible values: 0 .. DTV_ISDBT_SB_SEGMENT_COUNT-1 > > Note: This value cannot be determined by an automatic channel search. > > 5. DTV_ISDBT_SB_SEGMENT_COUNT > > This field only applies if DTV_ISDBT_SOUND_BROADCASTING is '1'. > > DTV_ISDBT_SB_SEGMENT_COUNT gives the total count of connected ISDB-Tsb > channels. > > Possible values: 1 .. 13 > > Note: This value cannot be determined by an automatic channel search. > > 6. Hierarchical layers > > ISDB-T channels can be coded hierarchically. As opposed to DVB-T in > ISDB-T hierarchical layers can be decoded simultaneously. For that > reason a ISDB-T demodulator has 3 viterbi and 3 reed-solomon-decoders. > > ISDB-T has 3 hierarchical layers which each can use a part of the > available segments. The total number of segments over all layers has > to 13 in ISDB-T. > > 6.1 DTV_ISDBT_LAYER_ENABLED (3b) > > Hierarchical reception in ISDB-T is achieved by enabling or disabling > layers in the decoding process. Setting all bits of > DTV_ISDBT_LAYER_ENABLED to '1' forces all layers (if applicable) to be > demodulated. This is the default. > > If the channel is in the partial reception mode > (DTV_ISDBT_PARTIAL_RECEPTION=1) the central segment can be decoded > independently of the other 12 segments. In that mode layer A has to > have a SEGMENT_COUNT of 1. > > In ISDB-Tsb only layer A is used, it can be 1 or 3 in ISDB-Tsb > according to DTV_ISDBT_PARTIAL_RECEPTION. SEGMENT_COUNT must be filled > accordingly. > > Possible values: 0x1, 0x2, 0x4 (|-able) > > DTV_ISDBT_LAYER_ENABLED[0:0] - layer A > DTV_ISDBT_LAYER_ENABLED[1:1] - layer B > DTV_ISDBT_LAYER_ENABLED[2:2] - layer C > DTV_ISDBT_LAYER_ENABLED[31:3] unused > > 6.2 DTV_ISDBT_LAYER*_FEC > > Possible values: FEC_AUTO, FEC_1_2, FEC_2_3, FEC_3_4, FEC_5_6, FEC_7_8, > > 6.3 DTV_ISDBT_LAYER*_MODULATION > > Possible values: QAM_AUTO, DQPSK, QAM_16, QAM_64, DQPSK > > Note: If layer C is DQPSK layer B has to be DQPSK. If layer B is DQPSK > and DTV_ISDBT_PARTIAL_RECEPTION=0 layer has to be DQPSK. > > 6.4 DTV_ISDBT_LAYER*_SEGMENT_COUNT > > Possible values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, -1 (AUTO) > > Note: Truth table for DTV_ISDBT_SOUND_BROADCASTING and > DTV_ISDBT_PARTIAL_RECEPTION and LAYER*_SEGMENT_COUNT > > PR | SB || layer A width | layer B width | layer C width | total > ----+----++---------------+---------------+---------------+------- > 0 | 0 || 1 .. 13 | 1 .. 13 | 1..13 | 13 > 1 | 0 || 1 | 1 .. 13 | 1..13 | 13 > 0 | 1 || 1 | 0 | 0 | 1 > 1 | 1 || 1 | 2 | 0 | 3 > > > 6.5 DTV_ISDBT_LAYER*_TIME_INTERLEAVING > > Possible values: 0, 1, 2, 3, -1 (AUTO) > > Note: The real inter-leaver depth-names depend on the mode (fft-size); the > values > here are referring to what can be found in the TMCC-structure - > independent of the mode. > > ----------------- > > > thanks for the feedback in advance, > Patrick. Patrick, It's extremely exciting to finally see this surfacing to the mailing lists -- It will be a great addition to linux-dvb to have support for the ISDB digital standards. One thing that I see missing right now is userspace utilities. Do you have any plans to add ISDB scanning support to dvb-apps, and tuning support to the *zap utility? This would be the best way to get the application developers started on incorporating ISDB support into the apps shipping today. Regards, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
