> For the complete documentation index, see [llms.txt](https://docs.tvheadend.org/documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tvheadend.org/documentation/setup/muxes-scan-files/scan-files.md). # Scan Files Scan files are used by TVHeadEnd (TVH) during the setup process to create muxes and scan for services available on those muxes.\ \ An excerpt from a scan file may look like this: `[CHANNEL]`\ `DELIVERY_SYSTEM = DVBT`\ `FREQUENCY = 226500000`\ `BANDWIDTH_HZ = 7000000`\ `CODE_RATE_HP = AUTO`\ `CODE_RATE_LP = AUTO`\ `MODULATION = QAM/64`\ `TRANSMISSION_MODE = 8K`\ `GUARD_INTERVAL = 1/16`\ `HIERARCHY = NONE`\ `INVERSION = AUTO` The location of the scan files may vary based upon the TVH version.\ \ `/usr/local/share/tvheadend/data/dvb-scan/`\ `/usr/share/tvheadend/data/dvb-scan/` Depending on the value of the `DELIVERY_SYSTEM`, TVH recognises the following parameters.
ParameterDVB-T/2DVB-S/2DVB-CATSCISDB-T
DELIVERY_SYSTEM✓✓✓✓✓
FREQUENCY✓✓✓✓✓
BANDWIDTH_HZ✓✓
CODE_RATE_HP✓
CODE_RATE_LP✓
MODULATION✓✓✓✓
TRANSMISSION_MODE✓
GUARD_INTERVAL✓✓
HIERARCHY✓
INVERSION✓✓✓✓✓
STREAM_ID✓✓
INNER_FEC✓✓
ROLLOFF✓
PILOT✓
PLS_CODE✓
POLARIZATION✓
SYMBOL_RATE✓✓
ISDBT_LAYERA_FEC✓
ISDBT_LAYERB_FEC✓
ISDBT_LAYERC_FEC✓
ISDBT_LAYERA_MODULATION✓
ISDBT_LAYERB_MODULATION✓
ISDBT_LAYERC_MODULATION✓
ISDBT_LAYERA_SEGMENT_COUNT✓
ISDBT_LAYERB_SEGMENT_COUNT✓
ISDBT_LAYERC_SEGMENT_COUNT✓
ISDBT_LAYERA_TIME_INTERLEAVING✓
ISDBT_LAYERB_TIME_INTERLEAVING✓
ISDBT_LAYERC_TIME_INTERLEAVING✓
### Accepted values The following values are accepted for the parameter fields.\ Please note that an 'accepted' value may not always be processed. ### DELIVERY\_SYSTEM NONE, **DVB-C**, **DVBC/ANNEX\_A**, **DVBC\_ANNEX\_A**, **ATSC-C**, CableCARD, **DVBC/ANNEX\_B**, **DVBC\_ANNEX\_B**, **DVB-C/ANNEX-C**, **DVBC/ANNEX\_C**, **DVBC\_ANNEX\_C**, DVBC\_ANNEX\_AC, **DVB-T**, **DVBT**, **DVB-T2**, **DVBT2**, **DVB-S**, **DVBS**, **DVB-S2**, **DVBS2**, DVB-H, DVBH, **ISDB-T**, **ISDBT**, ISDB-S, ISDBS, ISDB-C, ISDBC, **ATSC-T**, ATSC, ATSCM-H, ATSCMH, DTMB, DMBTH, CMMB, DAB, DSS, TURBO. ### FREQUENCY Frequency in hertz. ### BANDWIDTH\_HZ (Bandwidth in hertz)\ 1700000, 5000000, 6000000, 7000000, 8000000, 10000000. ### CODE\_RATE\_HP / CODE\_RATE\_LP / INNER\_FEC 1/2, 1/3, 1/4, 1/5, 2/3, 2/5, 2/9, 3/4, 3/5, 4/5, 4/15, 5/6, 5/9, 6/7, 7/8, 7/9, 7/15, 8/9, 8/15, 9/10, 9/20, 11/15, 11/20, 11/45, 13/18, 13/45, 14/45, 23/36, 25/36, 26/45, 28/45, 29/45, 31/45, 32/45, 77/90. ### MODULATION NONE, AUTO, QPSK, QAM4NR, QAM/AUTO, QAM-AUTO, QAM/16, QAM16, QAM/32, QAM32, QAM/64, QAM64, QAM/128, QAM128, QAM/256, QAM256, QAM/1024, QAM1024, QAM/4096, QAM4096,VSB/8, 8VSB, VSB/16, 16VSB, PSK/8, 8PSK, DQPSK, BPSK, BPSK-S, 16APSK, 32APSK, 64APSK, 128APSK, 256APSK,8APSK-L, 16APSK-L, 32APSK-L, 64APSK-L, 128APSK-L, 256APSK-L. ### TRANSMISSION\_MODE NONE, AUTO, 1k, 2k, 8k, 4k, 16k, 32k, C1, C3780. ### GUARD\_INTERVAL NONE, AUTO, 1/4, 1/8, 1/32, 1/16, 1/128, 19/128, 19/256, PN420, PN595, PN945. ### HIERARCHY NONE, AUTO, 1, 2, 4. ### INVERSION NONE, AUTO, ON, OFF. ### ROLLOFF 5, 10, 15, 20, 25, 35. ### PILOT NONE, AUTO, ON, OFF. ### PLS\_CODE (Physical Layer Scrambling)\ ROOT, GOLD, COMBO. ### POLARIZATION V, H, L, R, O. ### References \ \ \ \ \ --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.tvheadend.org/documentation/setup/muxes-scan-files/scan-files.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.