After I rendered all the JPEG and PNG images for my latest small project I followed my usual workflow in VSE and discovered the encoded video credits were of very poor quality. The credits are composed of RGBA PNG images while the main body of the animation are composed of JPEG iamges. After scratching my head a lot and comparing to completed projects with good quality credits I spotted I did not have RGB under output ticked on.
The rest of the animation did not seem to suffer without RGB on so I'd like to know why the credits benefited from it? I guess it has to do with the alpha channel of the PNGs.