ModRetro Chromatic Capture Acceptable Audio Quality
4In my previous video I made a video capture of the video output from the ModRetro Chromatic, an FPGA based handheld console which plays Game Boy and Game Boy Color cartridges. Video is sent from the console's USB port and shows up as a webcam on a PC but audio must be captured through the headphone jack. The audio in that video was very noisy. I mentioned how the noise was only present when I plugged in a USB cable into the console, which was required for video output. The result was less than ideal but nothing I did could improve the noise when cables for both the headphone jack and the USB port were connected to my PC. Most things made it worse.
Not satisfied with this result, I decided to try another device to record the audio. As I had no issues with using headphones with the USB cable, I grabbed an Zoom H1n Handy Recorder binaural microphone. This device runs on batteries and can record microphone input to a microSD card. The device also has a line input jack for recording and a line/headphone output jack. I connected my Chromatic's headphone jack to the H1n's line input and a pair of passive speakers to the H1n's line output so I could hear the audio playing. Connecting the line output from the H1n to the PC brought the noise back, so the audio recording device has to be electrically isolated from the video recording device.
Then with my Chromatic I used my EverDrive GB X7 to run the 144p Test Suite. I started the video and audio recording, then ran the Audio Sync test for a sync reference point. Then I switched over to Super Mario Land for a short demonstration of music and sound effects. When I finished level 1-1 I turned off both recordings and then used Audacity and VirtualDub2 to edit the audio and the video just at the sync pulse, then I combined the audio and upscaled the video.
The recording setup is far from convenient and not useful for streaming, but as long as you use separate devices to record audio and video, and do not have a common connection between them, you might get acceptable audio as well as video quality from the Chromatic.