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| >Video for Linux Two API Specification: Revision 0.24</TH |
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| NAME="RDS" |
| >4.11. RDS Interface</A |
| ></H1 |
| ><P |
| >The Radio Data System transmits supplementary |
| information in binary format, for example the station name or travel |
| information, on a inaudible audio subcarrier of a radio program. This |
| interface aims at devices capable of receiving and decoding RDS |
| information.</P |
| ><P |
| >The V4L API defines its RDS API as follows.</P |
| ><P |
| >From radio devices supporting it, RDS data can be read |
| with the <A |
| HREF="r14264.htm" |
| ><CODE |
| CLASS="FUNCTION" |
| >read()</CODE |
| ></A |
| > function. The data is packed in groups of three, |
| as follows:<P |
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| ><OL |
| TYPE="1" |
| ><LI |
| ><P |
| >First Octet Least Significant Byte of RDS Block</P |
| ></LI |
| ><LI |
| ><P |
| >Second Octet Most Significant Byte of RDS Block</P |
| ></LI |
| ><LI |
| ><P |
| >Third Octet Bit 7: Error bit. Indicates that an |
| uncorrectable error occurred during reception of this block. Bit 6: |
| Corrected bit. Indicates that an error was corrected for this data |
| block. Bits 5-3: Received Offset. Indicates the offset received by the |
| sync system. Bits 2-0: Offset Name. Indicates the offset applied to |
| this data.</P |
| ></LI |
| ></OL |
| ></P |
| ><P |
| >It was argued the RDS API should be |
| extended before integration into V4L2, no new API has been devised yet. |
| Please write to the Video4Linux mailing list for discussion: <A |
| HREF="https://listman.redhat.com/mailman/listinfo/video4linux-list" |
| TARGET="_top" |
| >https://listman.redhat.com/mailman/listinfo/video4linux-list</A |
| >. |
| Meanwhile no V4L2 driver should set the |
| <CODE |
| CLASS="CONSTANT" |
| >V4L2_CAP_RDS_CAPTURE</CODE |
| > capability flag.</P |
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