[linux-dvb] notes and code for HVR-1800 S-Video

djamil djamil at djamil.net
Tue Dec 2 07:29:34 CET 2008

I am trying to do the same thing on my HVR 1400, can you give me clues
on how i can hack it up

I want to get analog working for svideo/composite inputs ...

Any tools under windows to spy on it ...

best regards

Le samedi 22 novembre 2008 à 14:52 -0500, Jeff DeFouw a écrit :

> I compared the registers in different modes with the Windows driver for 
> my WinTV-HVR-1800 (CX23887 based, PCI-E).  Setting the AFE control 
> registers fixes bad and flickering colors in S-Video mode.  The same 
> register values are used for Composite.
> /* Set AFE control for Composite/S-Video input */
> cx25840_write4(client, 0x104, 0x071cdc00);
> In analog tuner mode, the values are the chip defaults (0x0704dd80), but 
> I've left the regs set for S-Video and didn't notice anything.
> To get the external audio input working (for Composite and S-Video 
> modes), the input needs to be set to AC97, unmuted, and the 
> microcontroller must be disabled (so it doesn't mute it).  The 
> microcontroller was always being enabled for some reason no matter the 
> audio source.
> /* Set Path1 to AC97 and unmute */
> cx25840_write4(client, 0x8d0, 0x00063073);
> With those two changes I am able to record S-Video and external audio 
> through the MPEG encoder.  I managed to hack the code up enough to get 
> all modes working based on the input setting.  It's not clear in the 
> existing cx23885-cx25840 framework how the audio input is supposed to be 
> configured.
> Other issues:
> The MPEG encoder video device randomly fails to start streaming, times 
> out, and returns an I/O error.  It's like something isn't being reset or 
> waited on properly during the setup.  The next attempt usually works, 
> but I can try 5 times and not succeed.
> The MPEG encoder video device rejects attempts to set the input and 
> other settings as the raw video device does.  The raw video device must 
> be used for configuration, so any application would have to do something 
> special with both devices to be fully functional.  Is there a reason for 
> that?
> Viewing the analog tuner over the raw video device and then using the 
> MPEG video device often causes the tuner video on both devices to be 
> scrambled.  Reloading the modules fixes it.  This only happens the first 
> time after boot.
> The cx23885-audio branch screws up the operation of my card.  
> Specifically the patch to cx23885_initialize that disables the write to 
> register 0x2 affects my board and scrambles the video and audio rate.  
> It even screws up the MCU firmware download.
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