Adobe Premiere Pro Forum
h.264 with Five Audio Channels?
h.264 with Five Audio Channels?
by Kevin Anton on Aug 8, 2019 at 8:53:32 am

Ultimately, I'm trying to create an ingest preset so that when I bring footage into Premiere, it will create proxies. I compared a handful of codecs (Prores Proxy, Dnx, Cineform) and none of them come anywhere close to h.264 when it comes to image quality and file size. They all create files that look worse while taking up ten times as much space as h.264.

The problem is my footage (Alexa Mini) has five channels of audio, and apparently h.264 does not support five channels of audio. All of the channels are blank audio from the camera, so I don't care about them, but Premiere will not ingest the footage using an h.264 proxy codec because the audio channels do not match.

Am I missing something here? 1. Why do video codecs even have varied audio options? 2. Why does h.264 not support five channels?

From looking at older threads, it seems like this was totally doable two years ago before they changed the export settings around. You could choose to export a Quicktime, then just pick the H.264 codec for the video and "uncompressed" for the audio, and you could set it to five channels. Now if you want h.264, you have to choose that as the filetype instead of Quicktime, and you don't have an uncompressed audio option. Why would they get rid of that ability?

Is there another codec that works as well as h.264 and allows more audio channels? (Like I said, Prores, Dnx, and Cineform are not good enough.)
My last resort is to batch remove every audio channel from the source files, but I'd rather not do that if I don't have to.

Re: h.264 with Five Audio Channels?
by greg janza on Aug 8, 2019 at 3:37:48 pm

You are correct that H264 is a fantastic codec to create high quality files at a very small file size. The problem though is that H264 is an acquisition format and delivery format but it shouldn't be used as an editing codec. The simple reason for this is that H264 is a codec that requires a lot of CPU processing power for playback.

Proxies are literally stand in files for the high resolution media so there's no need to get hung up on image quality when creating the proxies. And yes, you must create proxies with exact matching audio channels in order for Premiere to link them.

I would advocate that you use Cineform. It's an excellent codec that creates files at a variety of quality levels, has full customization of audio channels and is optimized for editing which means your Premiere project will work at maximum efficiency. And in 2019, the file sizes should be a non-issue since hard drive space is dirt cheap.

And if you really want to make the proxy creation workflow efficient use Resolve instead of Adobe Media Encoder.

Re: h.264 with Five Audio Channels?
by Kevin Anton on Aug 9, 2019 at 3:17:55 am

I had no idea that file size and CPU usage were not directly correlated. Thanks for the help. I guess I will just stick with Cineform after all, thanks to your confident reassurance.

(Proxy quality does matter a bit here, since I have a client eager to look at the nice footage throughout the edit process, and the source files play back choppy even after rendering. File size matters too, since I'd like to be able to fit all of the proxies on a portable drive for travel editing. Nevertheless, let's give Cineform a go!)

Can you explain how a Resolve workflow is more efficient?vNever done that. I'm working in Premiere, so it will create the proxies for me automatically, I just need Media Encoder to make the presets and then do the work.

Re: h.264 with Five Audio Channels?
by greg janza on Aug 9, 2019 at 7:54:34 pm

Resolve is better all around for the proxy creation process for two main reasons:

1. When making proxies in Resolve, you can continue working in Premiere.

2. Resolve has a simple button setting that allows for audio channels to match the source file. No need to customize an ingest or render preset.