I'm looking for a video player that doesn't stretch my 640x480 video files to full screen (1024x768), which degrades the quality IMHO.
Is such an app available?
OPLayerHD allows you to select the stretching mode, so you can select between full screen and actual ration of the video.
There is also a lite version, maybe you can try that one before buying the complete OPlayerHD
Alternativelly there was AVPlayerHD, which seems to be not available now.
How about nPlayer? It allows you to adjust the size of the video you're watching.
nPlayer provides high quality video play performance and easy control-UI supporting almost all kinds of video formats and codecs without file converting efforts.