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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_tI 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. -- 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