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.

[Carl Eugen Hoyos]

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