My video files contain 24 but audio, as well as any supplemental files I may use. Why does Vegas only allow 16 bit audio when rendering? There is no option to change it. Is it because of the render profile I use?
@anthony-chiappette That is quite normal, editing audio is done in the highest quality (e.g. 24bit), however rendering to a distribution media is usually down sampled (with dithering) to 16 bits.
16 bits is not bad quality, sufficient for playback on many consumer devices and standard for CDs (16-bit/44.1kHz). Do you want to deliver better quality than CD's?
However I do think the default render settings in VP23 with video and audio are a bit minimal on the audio bitrate.
In your screenshot I see you select or use 256 kb/s, I would increase that to 320 kb/s for stereo (and even higher for 5.1 audio). Contrary to the 16 bit output, you do can change the bitrate in the audio tab of the render profiles.
As @bitman said, a distribution media has its rule.
When you want rendering intermediate like the MXF, they all have 24bit depth: