OSSC + Puteltal Capture Card issues on Linux

[RobertTheSable]

This isn’t strictly an OSSC issue, but it’s somewhat related. I purchased the USB 4K Capture card(branded “PUTELTAL” on Amazon) that was shown by Voultar and RetroRGB as budget a option to capture the OSSC. It works in that it does seem to accept all the signals that the OSSC produces, however there are some issues in 4x and 5x modes.

In 5x mode, a back bar is added to the top of the image. This hasn’t been a huge deal as it doesn’t seem to cut off any important video signal, but it’s still a bit annoying.

The more serious issue is with any 960p output – the card crops the image down to 720p, which cuts off a significant chunk of the image.

Here are some samples:

• 480p 2x Mode.
• 480i 4x Mode.

I was wondering if anyone else had tried using this card on Linux and run into these issues, and if they’d found a workaround or not.

Here’s the output of v4l2-ctl –all for the card:

Driver Info:
        Driver name      : uvcvideo
        Card type        : UVC Camera (eba4:7588): 
        Bus info         : usb-0000:03:00.0-1
        Driver version   : 5.4.60
        Capabilities     : 0x84a00001
                Video Capture
                Metadata Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
        Width/Height      : 1280/720
        Pixel Format      : 'MJPG' (Motion-JPEG)
        Field             : None
        Bytes per Line    : 0
        Size Image        : 921600
        Colorspace        : sRGB
        Transfer Function : Default (maps to sRGB)
        YCbCr/HSV Encoding: Default (maps to ITU-R 601)
        Quantization      : Default (maps to Full Range)
        Flags             : 
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 1280, Height 720
        Default     : Left 0, Top 0, Width 1280, Height 720
        Pixel Aspect: 1/1
Selection Video Capture: crop_default, Left 0, Top 0, Width 1280, Height 720, Flags: 
Selection Video Capture: crop_bounds, Left 0, Top 0, Width 1280, Height 720, Flags: 
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 60.000 (60/1)
        Read buffers     : 0
                     brightness 0x00980900 (int)    : min=1 max=16 step=1 default=8 value=8
                       contrast 0x00980901 (int)    : min=1 max=16 step=1 default=8 value=8
                     saturation 0x00980902 (int)    : min=1 max=16 step=1 default=7 value=7
                            hue 0x00980903 (int)    : min=1 max=1 step=1 default=1 value=7
    white_balance_red_component 0x0098090e (int)    : min=513 max=513 step=513 default=513 value=257
   white_balance_blue_component 0x0098090f (int)    : min=1 max=1 step=1 default=1 value=7
                          gamma 0x00980910 (int)    : min=1 max=64 step=1 default=63 value=63
      white_balance_temperature 0x0098091a (int)    : min=1 max=1 step=1 default=1 value=63
                      sharpness 0x0098091b (int)    : min=1 max=16 step=1 default=2 value=2

[Harrumph]

The card is obviously set to capture 1280×720. Either change that value, or use a program like OBS to scale the video signal to 1280×720 beforehand.

[RobertTheSable]

The card is obviously set to capture 1280×720. Either change that value, or use a program like OBS to scale the video signal to 1280×720 beforehand.

I would except the card doesn’t present the option to select a higher resolution with 960p input.

Here are the resolutions the card reports are available in 960p mode:

$ v4l2-ctl --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'MJPG' (Motion-JPEG, compressed)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)

Compare this to what’s reported with 1080p input:

$ v4l2-ctl --list-formats-ext                                              
ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'MJPG' (Motion-JPEG, compressed)
                Size: Discrete 1920x1080
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)
                Size: Discrete 1280x720
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)

And 480p:

$ v4l2-ctl --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
        Type: Video Capture

        [0]: 'MJPG' (Motion-JPEG, compressed)
                Size: Discrete 720x480
                        Interval: Discrete 0.017s (60.000 fps)
                        Interval: Discrete 0.033s (30.000 fps)

These are the same options OBS shows.

I tested a bit passing the card to a Windows VM and saw the same behavior, so I believe the issue is on the hardware level.

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