A Video Group defines how Freevo will use it's available inputs as recording sources. My installation has the following Video Groups:

VIDEO_GROUPS = [
        #VideoGroup[0]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='tuner',
                        input_num=0,
                        tuner_norm='NTSC',
                        tuner_chanlist='us-cable',
                        desc='Local Cable',
                        group_type='ivtv',
                        record_group=1),
        #VideoGroup[1]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='tuner',
                        input_num=0,
                        tuner_norm='NTSC',
                        tuner_chanlist='us-cable',
                        desc='Local Cable Recording',
                        group_type='ivtv',
                        record_group=None),
        #VideoGroup[2]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='composite',
                        input_num=1,
                        tuner_type='external',
                        desc='Composite Input',
                        group_type='ivtv',
                        record_group=3),
        #VideoGroup[3]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='composite',
                        input_num=1,
                        tuner_type='external',
                        desc='Composite Input Recording',
                        group_type='ivtv',
                        record_group=None),
        #VideoGroup[4]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='svideo',
                        input_num=3,
                        tuner_type='external',
                        desc='S-Video Input',
                        group_type='ivtv',
                        record_group=5),
        #VideoGroup[5]
                VideoGroup(
                        vdev='/dev/video0',
                        adev=None,
                        input_type='svideo',
                        input_num=3,
                        tuner_type='external',
                        desc='S-Video Input Recording',
                        group_type='ivtv',
                        record_group=None)
]

Here's how each element of a Group breaks down:

1. vdev: The actual video device used by this group. /dev/video0 is typical but your system may be different.

2. adev: The actual audio device used by this group. I'm using a Hauppauge PVR 150 card which has it's own MPEG2 encoder so I don't have an adev entry. Other TV cards may require this entry.

3. input_type: Named input type.

4. input_num: Actual input number of your TV card. Denotes which input to use, i.e. Tuner, Composite, S-Video, Tuner2, etc. Check your recordserver.log for more information on your input numbers as these vary from card to card.

5. tuner_norm: Tuning standard to use with this tuner. Typical options are PAL, NTSC and SECAM. Applies to only to the internal tuner(s) of a TV card.

6. tuner_chanlist: Defines the channel list type to use. This varies by specific location. Your localconf.py will have more details.

7. tuner_type: Used to denote external tuners only, i.e. composite or S-video input from a VCR or DVD player.

8. desc: Friendly description.

9. group_type: Seems to point to the type of hardware device; ivtv for most Hauppauge cards, webcam for webcam, etc.

10. record_group: Defines which Video Group to use to record from a specific input. Note the comments included above. Video Group 0 points to Video Group 1 for use as a recording input. Video Group 2 points to Video Group 3, and so on. These pointers allow the use of multiple cards each with multiple tuners. See MultiTunerConfig for more info.