For the voice recorder, the quality of voice recording is affected by recording bit rate, the unit is Kpbs, the larger the recording bit rate, the higher quality the recording voice will be, and the sound will be more clear. By contrast it will take more storage space. Please choose the products according to practical demands. And the voice recorder on market will provide several recording bit rate for setting.
For the video recorder, the quality of video taking is affected by resolution, The higher the resolution, More clear the video will be. By contrast it will take more storage space. The most common resolution is HD1080p , it's higher than 720p , which will make the video sharper. Different technique make the product different. It's better to have a sample video before you place an order, then to see whether meet you demands.