Hi Daniel,

Em Fri, 21 Aug 2020 09:58:44 -0300
"Daniel W. S. Almeida" <[email protected]> escreveu:

> From: "Daniel W. S. Almeida" <[email protected]>
> 
> This series is work in progress. It represents the current work done on a
> virtual DVB driver for the Linux media subsystem. I am new to the media
> subsystem and to kernel development in general.
> 
> This driver aims to:
>       - Serve as template for new DVB driver writers
>       - Help userspace application writers in general
>       - Push fake audio/video to userspace for testing
>       purposes
>       - Push debug information to userspace via debugfs
> 
> Current state for this driver:
>       - Driver generates PSI information (PAT, PMT, SDT)
>       - Driver generates PCR packets
>       - Driver generates NULL packets for padding
>       - PCM audio stream is decoded by ffmpeg, but no audio is heard yet.
> 
> changes in v10:
>       s302m encoder got reworked

Thanks for all the hard work on it. Very much appreciated!

I finally found some time to test it. For now, just a quick
test from my side, without passing any arguments to the
driver.

See enclosed.

While there are still a few issues there, I'm considering applying
this series for Kernel 5.10.

My plan is to write some patches on the top of yours, in order to
address the problems I'll find on it. If not something more critical
won't be solved in time, we may still add it at staging/media. 
Let's see.

The problems I noticed so far are:

        1. rmmod doesn't work;
        2. dvbv5-stats doesn't seem to be working properly, as
           it is reporting signal strengh with a percentage
           (same for Carrier S/N ratio);
        3. dvbv5-zap wrote an empty audio file (without -P flag).
           Probably there are still some issues at the program
           channel descriptor or service;
        4. The provider service field is null. Perhaps we could
           add some string there, like "linuxtv.org".
        5. Maybe we could also add a simple NIT table, just to
           avoid dvbv5-scan to wait for it until timeout.

Also, it probably makes sense to add a debugfs interface in
order to allow injecting errors at the stream at runtime.

Regards,
Mauro

---

        $ dvbv5-scan -v foobar
        using demux 'dvb0.demux0'
        Device Dummy demod for DVB-T/T2/C/S/S2 (/dev/dvb/adapter0/frontend0) 
capabilities:
             CAN_FEC_1_2
             CAN_FEC_2_3
             CAN_FEC_3_4
             CAN_FEC_4_5
             CAN_FEC_5_6
             CAN_FEC_6_7
             CAN_FEC_7_8
             CAN_FEC_8_9
             CAN_FEC_AUTO
             CAN_GUARD_INTERVAL_AUTO
             CAN_HIERARCHY_AUTO
             CAN_INVERSION_AUTO
             CAN_QAM_16
             CAN_QAM_32
             CAN_QAM_64
             CAN_QAM_128
             CAN_QAM_256
             CAN_QAM_AUTO
             CAN_QPSK
             CAN_TRANSMISSION_MODE_AUTO
        DVB API Version 5.11, Current v5 delivery system: DVBC/ANNEX_A
        Supported delivery systems: 
             DVBT
             DVBT2
            [DVBC/ANNEX_A]
             DVBS
             DVBS2
        Frequency range for the current standard: 
        From:            51.0 MHz
        To:              2.15 GHz
        Step:            62.5 kHz
        Tolerance:       29.5 MHz
        Symbol rate ranges for the current standard: 
        From:            1.00 MBauds
        To:              45.0 MBauds
        Failed to guess country from the current locale setting.
        
        ERROR    command BANDWIDTH_HZ (5) not found during retrieve
        Cannot calc frequency shift. Either bandwidth/symbol-rate is 
unavailable (yet).
        Scanning frequency #1 330000000
        FREQUENCY = 330000000
        MODULATION = QAM/AUTO
        INVERSION = AUTO
        SYMBOL_RATE = 6940000
        INNER_FEC = AUTO
        DELIVERY_SYSTEM = DVBC/ANNEX_A
        Got parameters for DVBC/ANNEX_A:
        FREQUENCY = 330000000
        MODULATION = QAM/AUTO
        INVERSION = AUTO
        SYMBOL_RATE = 6940000
        INNER_FEC = AUTO
        DELIVERY_SYSTEM = DVBC/ANNEX_A
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        dvb_read_sections: waiting for table ID 0x00, program ID 0x00
        dvb_parse_section: received table 0x00, extension ID 0x0744, section 0/0
        dvb_parse_section: table 0x00, extension ID 0x0744: done
        PAT
        | table_id         0x00
        | section_length      13
        | one                 2
        | zero                0
        | syntax              1
        | transport_stream_id 1860
        | current_next        1
        | version             1
        | one2                3
        | section_number      0
        | last_section_number 0
        |\ 1 program pid
        |  pid 0x0101: service 0x0880
        Program #0 ID 0x0101, service ID 0x0880
        dvb_read_sections: waiting for table ID 0x02, program ID 0x101
        dvb_parse_section: received table 0x02, extension ID 0x0880, section 0/0
        dvb_parse_section: table 0x02, extension ID 0x0880: done
        PMT
        | table_id         0x02
        | section_length      24
        | one                 2
        | zero                0
        | syntax              1
        | transport_stream_id 2176
        | current_next        1
        | version             1
        | one2                3
        | section_number      0
        | last_section_number 0
        |- pcr_pid          0200
        |  reserved2           7
        |  descriptor length   0
        |  zero3               0
        |  reserved3          15
        |\
        |- stream 0x0111: ISO/IEC 13818-1 Private Data (6)
        |    descriptor length   6
        |        0x05: registration_descriptor
        |           42 53 53 44                                        BSSD
        |_  1 streams
        dvb_read_sections: waiting for table ID 0x40, program ID 0x10
        ERROR    dvb_read_sections: no data read on section filter
        ERROR    error while reading the NIT table
        dvb_read_sections: waiting for table ID 0x42, program ID 0x11
        dvb_parse_section: received table 0x42, extension ID 0x0744, section 0/0
        dvb_parse_section: table 0x42, extension ID 0x0744: done
        SDT
        | table_id         0x42
        | section_length      48
        | one                 2
        | zero                1
        | syntax              1
        | transport_stream_id 1860
        | current_next        1
        | version             1
        | one2                3
        | section_number      0
        | last_section_number 0
        | network_id          1860
        | reserved            255
        |\
        |- service 0x0880
        |   EIT schedule          0
        |   EIT present following 0
        |   free CA mode          0
        |   running status        4
        |   descriptor length     31
        |        0x48: service_descriptor
        |           service type  1
        |           provider      '(null)'
        |           name          'S302m: Sine Wave PCM Audio'
        |_  1 services
        Service S302m: Sine Wave PCM Audio, provider (null): digital television
        Storing as channel S302m: Sine Wave PCM Audio
        
        $ dvbv5-zap -c dvb_channel.conf "S302m: Sine Wave PCM Audio" -m
...
         PID           FREQ         SPEED       TOTAL
            0     25.07 p/s   36.826 Kbps       55 KB
           17     25.07 p/s   36.826 Kbps       55 KB
          257     25.07 p/s   36.826 Kbps       55 KB
          273   1335.19 p/s    1.915 Mbps     2943 KB
          512     25.07 p/s   36.826 Kbps       55 KB
         8191  16775.59 p/s   24.062 Mbps    36974 KB
        TOT    18211.08 p/s   26.121 Mbps    40138 KB
        
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        
        
        $ dvbv5-zap -c dvb_channel.conf "S302m: Sine Wave PCM Audio" -t 30 -o 
pcm_audio.ts
        using demux 'dvb0.demux0'
        reading channels from file 'dvb_channel.conf'
        service has pid type 06:  273
        tuning to 330000000 Hz
               (0x00) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        Record to file 'pcm_audio.ts' started
        Forcing program stop due to timeout or terminate signal
        
        $ ls -l pcm_audio.ts
        -rw-r--r-- 1 mchehab mchehab 0 Sep 11 09:46 pcm_audio.ts

        $ dvbv5-zap -c dvb_channel.conf "S302m: Sine Wave PCM Audio" -t 30 -o 
pcm_audio.ts -P
        using demux 'dvb0.demux0'
        reading channels from file 'dvb_channel.conf'
        service has pid type 06:  273
        tuning to 330000000 Hz
        pass all PID's to TS
          dvb_set_pesfilter 8192
        dvb_dev_set_bufsize: buffer set to 6160384
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0
        Record to file 'pcm_audio.ts' started
        received 103809840 bytes (3379 Kbytes/sec)
        Lock   (0x1f) Signal= 0.00% C/N= 0.00% UCB= 0 postBER= 0

        $ ls -lh pcm_audio.ts
        -rw-r--r-- 1 mchehab mchehab 100M Sep 11 09:54 pcm_audio.ts


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