[Bug]: Only getting first frame of audio when exporting section of movie

### What happened?

We're seeing an issue in rv v3.1.0 where an exported movie is missing audio.

The steps to generally reproduce are:

1. Open a long movie file in rv (Note: the one I used was >45,000 frames, >1800s)
2. set an in point and out point late in the video, a couple frames apart
3. `File` > `Export` > `Quicktime Movie...`
4. Open up the exported movie file, we are seeing that it is missing audio past the first frame

### List all the operating systems versions where this is happening

RHEL 9.6

### On what computer hardware is this happening?

Workstation type: HP HP Z8 G4 Workstation, GPU: nVidia NVIDIA RTX A6000, CPU: Intel Xeon Gold 6242R 3.1 (40 cores), Memory / RAM: 191590MB (32767MB SWAP)

### Relevant console log output

```shell

```

### Environment variables

_No response_

### Extra information

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start with the File > Export > Quicktime Movie path in RV v3.1.0 and reproduce the issue using a long movie with a late, short in/out section on RHEL 9.6. Trace how the export handles audio after the first frame. Done means the exported section retains audio throughout, not only at its first frame.

Written by the indexing model from the issue text.