QtMultimedia, RadioData object



  • Hi all,

    i am trying to use this QML object on a linux based system using an fm radio chip, but no rds data is displayed from the object. If i read rds data using a console tool, seems data are there:

    [system@localhost user]$ rds-ctl -R
    Using device: /dev/radio0

    TP: yes TA: no
    PI: a000
    Area Coverage: Local
    PTY: 10 -> Pop Music
    MS Flag: Music
    Time: Thu Aug 20 10:59:00 2015

    Language: 21 -> Italian
    Time: Thu Aug 20 10:59:00 2015

    Time: Thu Aug 20 10:59:00 2015

    Error reading from device (no RDS data available)

    Summary of valid RDS-fields:
    PI: a000
    Area Coverage: Local
    PTY: 10 -> Pop Music
    Time: Thu Aug 20 10:59:00 2015

    TP: yes TA: no
    MS Flag: Music
    Language: 21 -> Italian

    Enhanced Other Network information: 1 channels
    PI(ON 00) = 0000
    PS(ON 00) =
    TP(ON 00): no

    RDS Statistics:
    received blocks / received groups: 100 / 25
    block errors / group errors: 0 (0.00%) / 0
    corrected blocks: 0 (0.00%)
    Group 00: 10
    Group 01: 3
    Group 02: 2
    Group 03: 0
    Group 04: 4
    Group 05: 0
    Group 06: 0
    Group 07: 0
    Group 08: 0
    Group 09: 0
    Group 10: 0
    Group 11: 0
    Group 12: 0
    Group 13: 0
    Group 14: 3
    Group 15: 3
    [system@localhost user]$

    I am wondering how the RadioData object interact with v4l2 library, and how i could debug the issue.

    Many thanks
    angelo


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Did you also check the Radio Overview Chapter ?



  • Hi,

    well, from that page:

    Radio Implementation Details

    The actual level of support depends on the underlying system support. It should be noted that only analog radio is supported, and the properties of the radio data component will only be populated if the system radio tuner supports RDS.

    This is not totally true. My driver supports RDS and rds-ctl tool reads the data. While RadioData object is not accessing the driver fops_read at all (checked with some printk at driver level).
    So, mainy, in linux at least, even using v4l2 support, radioData seems to do nothing.
    Investigating.


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