I have a video file with audio. ffprobe reports two different numbers: Sampling rate and Frame rate. I understand the 48kHz rate--there are 48,000 audio samples every second. What is the other number, and what is a "frame" in this context?

 ID                                       : 2
 Format                                   : AAC
 Sampling rate                            : 48.0 kHz
 Frame rate                               : 46.875 FPS (1024 SPF)

1 Answer 1


Audio samples are encapsulated into frames as well. For PCM, the framing is notional, but for DCT-based codecs, it's a basic requirement.

AAC typically bundles 1024 samples per frame, so 1 second of 48000 samples represents 48000/1024 = 46.875 FPS

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