SiliconDust HDHomeRun Manual de usuario descargar pdf (Pagina 12)

filter automatically. There is a bug in one of the standard Windows BDA components that prevents

this from working.

Windows 7: The Windows BDA system supports the PID filtering APIs and will set the PID filter

automatically when using the standard Windows BDA components.

HDHomeRun Setup will auto-detect if the OS has working built in PID filter support and can

configure the driver appropriately.

MCE 2005 or Windows 7 is required to test the built in Windows hardware PID filter handling. It is

important to test both changing to a new frequency and changing to a different sub-channel on

the same frequency.

Built in Windows PID handling cannot be used with normal XP (non MCE 2005) or normal Vista

(non WMCTVP).

US digital cable support:

The HDHomeRun BDA driver supports native US-QAM (ClearQAM) operation, as well as providing

a channel remap mechanism to allow US digital cable to be used with legacy ATSC-only

applications.

The modulation is auto-detected by the HDHomeRun. The only application change typically

needed to tune a native digital cable channel is to pass a cable frequency rather than an OTA

frequency.

Modulation:

US digital cable providers mostly use QAM256 modulation, however can also use QAM64 and/or

8VSB modulation.

The HDHomeRun uses the modulation type set by the application as a hint, but always auto-

detects the modulation type.

The general-purpose method for detecting if a driver supports auto-modulation detection is to

query the "IBDA_AutoDemodulate" interface. If this interface exists, call put_AutoDemodulate. If

this function returns OK then the tuner supports automatic modulation detection.

Channel map:

There are three common channel number to frequency tables used by US cable providers - Cable,

IRC, and HRC.

The Cable and IRC channel maps are almost identical. With the exception of channels 5 and 6, all

IRC channels are within 25kHz of the matching Cable channels (less than the tuning resolution of

a typical tuner).

To test all US cable channels an application must test all Cable channels, all HRC channels, and

IRC channels 5 and 6.

The HDHomeRun driver can operate in one of four modes:

Native: the application is responsible for setting the frequency. The HDHomeRun will tune the

requested frequency (plus 1.75MHz to convert the requested frequency from NTSC video carrier

frequency to digital center frequency).

AutoUSCableMap: used for legacy applications only support the Cable channel map. The

HDHomeRun driver will look up the requested frequency and compare with the channel

configuration recorded by HDHomeRun Setup. The requested frequency is converted to a HRC or

IRC frequency as needed.

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 23 24

Sin comentarios

SiliconDust HDHomeRun Manual de usuario Pagina 12