I found out how I could check the IVTV configuration: /home/mythtv$ v4l2-ctl --all. The output is:
Driver Info: Driver name : cx8800 Card type : Hauppauge WinTV-HVR1300 DVB-T/H Bus info : PCI:0000:00:08.0 Driver version: 6 Capabilities : 0x05010011 Video Capture VBI Capture Tuner Read/Write Streaming Format Video Capture: Width/Height : 320/240 Pixel Format : BGR3 Field : Interlaced Bytes per Line: 960 Size Image : 230400 Colorspace : Unknown (00000000) Format VBI Capture: Sampling Rate : 35468950 Hz Offset : 244 samples (6.87926e-06 secs after leading edge) Samples per Line: 2048 Sample Format : GREY Start 1st Field : 6 Count 1st Field : 17 Start 2nd Field : 318 Count 2nd Field : 17 Video input : 0 (Television) Frequency: 0 (0.000000 MHz) Video Standard = 0x000000f7 PAL-B/B1/G/I/D/D1/K Tuner: Capabilities : 62.5 kHz multi-standard Frequency range : 0.0 MHz - 268435455.9 MHz Signal strength : 0% Current audio mode : mono Available subchannels: 1