Rendering videos at default bitrate

nikos_xrim wrote on 5/10/2024, 5:11 PM

Greetings to the community,

I've been using this editing software for the past few months, and particularly the version 21.

However, although I enjoy a lot the user interface and generally the editing options/experience compared to other editing software, I've come across a matter that subjectively speaking, concerns me.

I refer to the rendering section, where you get to specify the output quality. Despite having a ton of options, I can't seem to find a particular one that will export my project in the exact same bitrate, as it was recorded at.

I usually work on videos which are encoded with Constant Bit Rate, meaning the data rate is fixed for every frame. When it comes to exporting a project, I always aim to keep the best quality possible, which most of the times entails a larger file size than needed. The rendering settings I use, can be found in the former attached screenshot (Encode Mode, Preset, RC Mode), and as seen, I get to make a selection within a few choices that do not suit me best. Let me elaborate.

Suppose you have a video, captured by your Sony camera at 7,500 kbps. You load it on the software, cut out some scenes, add a few visual effects and it's done. When it comes to exporting it, keeping it at best quality means that 10,000 kbps in Vegas Pro, is the only option that can serve the purpose. Something that in the rendering section of VideoPad (another editing software), would save up space, by simply selecting "Default Quality / Filesize", as seen in the latter attached screenshot. The resulted video file, would have bitrate same as the original video had, 7,500 kbps.

My query is how to define the output video quality at keeping the exact (if possible) bitrate, as done so in VideoPad, in order to avoid any excessive (needless) additional file size as a result of higher unnecessary data rate. Moreover, I'd like to know if there's a way I can re-export videos with higher bitrate than needed, by reducing the said data rate as much as possible to a point, where quality is fully preserved.

Thanks in advance.

 

Comments

EricLNZ wrote on 5/10/2024, 6:38 PM

Which render template are you using and can you not type in the bitrate value you require?

mark-y wrote on 5/10/2024, 7:57 PM

I can't seem to find a particular one that will export my project in the exact same bitrate, as it was recorded at.

As Eric mentioned, you can type the bitrate you want into most templates. However:

Vegas is an encoder, and not a muxer. Since it renders what is on the timeline, the output bitrate is entirely unrelated to the input bitrate, unless you are smart rendering. That feature is limited to only a couple of older codecs (AVI and MPEG-2), which are not general acquisition or delivery codecs.

Relative bitrate depends on resolution, frame rate, compression ratio, bit depth, chroma subsampling, and about two dozen other factors that you are not normally exposed to in the rendering templates.

Therefore, matching the bitrate is an unnecessary exercise, if you expect that doing so will exactly match the encoding properties of the original, with regards to quality. Depending on the type of compression you choose, the resulting files can be many time larger, or many times smaller than your original, with no direct relationship to the quality of the original.

There are some free third party muxers that will do what you want, but they are not nonlinear editors. ffmpeg is a command line utility, Shutter Encoder is a favorite of many editors here.

Tmpgenc Smart Render 6 is a paid solution with cutting, joining, and some editing capabilities that you may want to look at.

Since encoding and muxing are two entirely separate functions requiring different, independent processing engines, commercial dedicated nonlinear editors such as Vegas don't have such a thing, at least not that I am aware of.

3POINT wrote on 5/11/2024, 2:20 AM

When it comes to exporting a project, I always aim to keep the best quality possible,

 

Bitrate only is not a measure for quality.