Add support for encoding with audio from a path

[ksmoore17]

This adds support for encoding with an audio stream from a file path along with an option to provide an output audio codec.

Strings audio_path and audio_codec can be provided to the write_frames method.

It outputs a warning but successfully encodes the video when the stream provided as audio_path has no audio stream. It also adds an audio_codec key to the metadata when reading if an audio stream is present - with output gathered in a similar way to the video metadata.

Tried to keep it minimal; let me know if you want me to change anything.

50

[almarklein]

Late reply due to holidays & moving.

This looks really nice, thank! Just a few minor questions/comments.

[ksmoore17]

Not a problem. That linked issue is funny because I decided to add to the metadata mostly because it was useful for testing. Would you like me to squash commits when I add -an and the documentation of default behavior?

[almarklein]

No need to squash. We can squash-merge.

[ksmoore17]

Think the link I shared was only about video codecs. I believe the command line behavior for audio codecs is more like - if a format requires a less "standard" codec, you must specify one of these. That means either discovering each of cases and putting an if statement based on the format to set to one of its viable audio codecs, or letting ffmpeg give an error message.

[almarklein]

Looking good, is this ready from your end?

[ksmoore17]

Yes

[almarklein]

Thanks!