Low quality mp4 renders I have imported a 337 MB mp4 video file with no audio into Blender. In Blender, I am primarily just adding audio and then rendering back out to mp4. However, the rendered video quality is drastically lower, making much of the text in the video unreadable. The size of the output file is 65.7 MB.

In this image you can see my output settings:


Can anyone tell me what I am doing wrong? How can I get a higher quality render to mp4?
You should increase the bitrate. It determines the compression of the video data.
A starting point could be to set the bitrate as least as high as in the input file, and then add the Mp3 rate of 192kbs.

1920 x 1080 = 2,073,600 pixel count 
24 frames per second 
4 = High Motion 

(2,073,600 x 24) x 4 x 0.07 = 13,934,592 bps / 1024 = 13,608 kbps bitrate


See sections 4 (Quality versus Streaming) and 5 (Starting Points), in this tutorial.