I have to compile FFmpeg for iOS using an external build script, but when I am debugging I see assembler if I delve too deep into libavformat library functions:
So it appears that the issue is that I was compiling libavcodec.a, libavformat.a, etc into a single static library in my FFmpegWrapper project (libFFmpegWrapper.a), which I was then including as a static library in the containing project called LiveStreamer. Moving the .a files and adding the source files (not added to the build target) to the LiveStreamer project fixed the issue.
If anyone runs into this in the future, feel free to drop me a line because I was struggling with this for days.