Playback lag caused by audio data on the audio tracks?

[NwProPr]

Hello,

Source footage

Camera: Sony PXW-FX6 / Sony PXW-FX9

MPEG-4 XAVC-I/H.264

Type: MXF File Size: 6,95 GB

Image Size: 1920 x 1080

Frame Rate: 25,00

Source Audio Format: 48000 Hz - 24-bit - 8 Channels

Project Audio Format: 48000 Hz - 32 bit floating point - 8 Channels

Total Duration: 00:07:58:13

Pixel Aspect Ratio: 1,0

Alpha: None

Color Space: Rec. 709

Color Space Override: Off

Input LUT: None

MXF File details:

Wrapper type: MXF OP1a (type: SingleItem SinglePackage MultiTrack Stream Internal)

File generated by: Sony, Mem (2.00)

AVCI 100

Bitstream Format: Sony

Gamma: S-Log3 Cine

When I import a clip in Premiere to create a new Sequence (whether its an XDCAM HD 422 preset or a matching one to the footage), the playback is slightly lagging and not optimal. The codec uses intraframe, so one would assume playback should be as smooth as a ProRes, for example.

When dragging a clip on the timeline, playback is not terrible, but when you scroll through the clip (or you manually put the playhead on several timecodes in a fast pace), Premiere obviously needs some time to keep up. It needs a second to actually start playback after you hit the spacebar.

Now here is the interesting part:

When I remove the 8 audio tracks and just leave the video stream, the playback is smooth. Even when scrolling in a fast pace. Basically what I need. Not just for this one clip, but because this project will house a gazillion amount of clips, and previous projects have proven the sequence got slower by the time it got heavier.

When I drop a ProRes clip on the same timeline (where the AVC clip is being choppy), the playback of the ProRes is smooth as can be.

Is there a fix?
My question is: what can I do to make playback smoother? It seems like the audio is the bottleneck here. Might this be a setting in Premiere or is this just what it is? Would creating Audio Previews (Render Audio) for ALL footage that is imported be a solution? Generating audio waveforms doesn't seem to be the fix.

It's pretty time consuming to be forced to transcode all the footage, also because the video itself seems fine.

Thank you for any input! 🙂

[Michael Grenadier]

I strongly recommend a proxy workflow but if you don't want to spend the time, try this.  Select a clip in project window and right click and choose modify:  audio channels and turn off all but the crucial ones...  see if this improves the performance.  

[NwProPr]

Hi, thank you for your reply.

This project will contain a lot of footage. I'm estimating a total of 6 TB (3 cameras shooting over a period of 8 days). After filming is finished, I have two days to prepare the Premiere project. However, there is an option to transcode all footage after each shooting day to work ahead of time.

Wouldn't these MXF files be 'native' enough for Premiere to playback smoothly? It's 'only' 1080p. Or is it because these the codec is based on MPEG-4?

Proxy workflow: Multichannel audio

As we've experienced, using the internal ingesting workflow to create proxies doesn't work great with 8-channel MXF files. When you create a proxy (even using ingest presets) and try to maintain 8 channels, Premiere seem to 'overwrite' the proxies, visible in the timeline, with only 2 audio channels.

Therefore, when we use proxies on 4K UHD projects, this is our workflow:

1. Create proxies manually, using Media Encoder (ProRes 1080p, including 8 mono tracks)

2. Import into Premiere, Reconnect the original files from the project bin

Would you say this is also the best method for all Premiere projects, shot with these cameras? Creating lower res ProRes proxies, import them in Premiere, reconnect them to the original files using the Proxy menu (so you can toggle the proxy button) and from there start editing.

Besides the footage from the cameras, we'll also work with GoPro footage, for example. I guess all it also applies to that footage?

Modify Audio Channels
From what I can tell this doesn't really change the responsiveness. I disabled 7 audio tracks to see if 1 audio track would make it less choppy, but that wasn't the case. When I literally delete the audio tracks it does.

Thanks!

[Michael Grenadier]

yeah, mxf files are not ideal...  I'm working on a large documentary project with at least 30 hrs of 4k 2 camera interviews and we have some music performance footage shot with 3 and 4 cameras.  and using the proxy workflow does just fine...  What proxy preset are you using?   We've been using a lower resolution pro res proxy preset...     And fwiw, there have been many posts here about issues with gopro footage, so transcoding to prores might be a good idea...

[NwProPr]

Good advise on the GoPro footage. I did read a few things about that myself, however, I didn't really had any issues with it so far.

The director and producers don't like to work in low-low res quality time lines, so therefore, for our 4K productions, I'm using 1080p ProRes proxies (which work smoother than smooth). Each source resolution (both 4096x2160 and 3840x2160) has its own preset for Media Encoder. It's basically a custum copy of the Apple ProRess 422 Proxy preset where the resolution is changed to 1920x1080 or 2048x1080 (audio remains 48kHz/24-bit).

I will do a few tests to see how long the transcodes take and what the extra file size would be.

Thanks again!

[Michael Grenadier]

gotta say that the proxy format we're using looks pretty good.  I'll be at the clients tomorrow and double check the format.  Client control is never easy, but might be worthwhile doing a test with a lower resolution proxy and showing it to them and see if they might be satisfied.    And the timeline will be full resolution, just referencing the proxies when you have that turned on.    Also, you might tell us your system specs including OS version, Premiere version, amount of RAM, Hardware specs including graphics card and storage..  might have something to do with your performance problems...  

[NwProPr]

I do have to admit, in this specific case, we're talking about iMac Pro 2017 sets. However, the audio issue from my first post also occurs on the latest Mac Studio Ultra (we have one of those as well). Specs come down to CPU: 3 GHz 10-Core Intel Xeon W / GPU: Radeon Pro Vega 56 8 GB / RAM: 64 GB 2666 MHz DDR4 / SSD: 1TB / OS: Mac OS Ventura 13.2.1 / Premiere: 23.2

In general there aren't a lot of performance issues. And like I said, the 1 second delay from my first post isn't the end of the world. It was just very obvious that the problem seemed to be 'solved' when I remove the audio (which would've been weird, since audio isn't the biggest load on these files).

I will try a proxy with a lower res as well.

[P26259509ey04]

Yes. I have exactly the same issue. It definetly seems to be an audio issue. Did you ever find a solution?

[P26259509ey04]

In fact did you try unselecting "Sum multichannel outputs to mono in Source Monitor"

It seems to have helped for me for now.

You can find it in Premire Pro > Preferences > Audio

[Michael Grenadier]

always important to provide us with some information.  Never easy to troubleshoot premiere problems from a distance so please tell us your system specs: OS version, Premiere version, amount of RAM, Hardware specs including graphics card and if you have any 3rd party plugins installed for Premiere... Also, sequence settings and clip properties can also help. Although you can throw almost any format into premiere, some formats can be problematic, particularly on an underpowered system.

And have you tried changing your audio hardware input in premiere preferences to "none?"  This seems to solve a lot of problems.  

[Parnika33850194cehd]

Also experiencing the same issue. Let me know if theres a solution

[Michael Grenadier]

Never easy to troubleshoot premiere problems from a distance so please tell us your system specs: OS version, Premiere version, amount of RAM, Hardware specs including graphics card and if you have any 3rd party plugins installed for Premiere...  Also, the clip properties, the camera the material was shot on and your sequence settings.`  If you need help providing any of this info, post back...