Crackling noises in audio on iPod

[forthrin]

Some converted audio and video files get sporadic cracking noises during playback on an iPod Nano 3rd generation.

It can happen dozens of times during 30 minutes. Some times 3 times per second, some times 20 seconds apart. There is no clear pattern.

Enclosed is a small excerpt that includes:

1. An original input file
2. The output file from FFmpeg
3. What the output file sounds like when played on the iPod (played through a speaker and recorded with a microphone)

The command line was a simple ffmpeg -i original.ac3 converted.m4a. Version is latest Git head, run on macOS.

What could cause these crackling noises? Is this a known issue? How can I prevent them from occurring?

[forthrin]

I forgot to mention that the crackling noise only comes from the LEFT audio channel. The sound in the right channel is always fine.

Also, the crackling always happens in the same places, so it has something to do with the audio data, or how the iPod interprets them, since the file plays fine in other players on macOS.

[Carl Eugen Hoyos]

Please provide the command line you tested together with the complete, uncut console output to make this a valid ticket.