avgetbytespersample

av_get_bytes_per_sample is a helper function in FFmpeg’s libavutil that returns the number of bytes required to store a single sample for a given AVSampleFormat. It is commonly used when allocating or processing audio buffers to understand how much memory one sample occupies per channel.

The function signature is int av_get_bytes_per_sample(enum AVSampleFormat sample_fmt). It returns the number of bytes per sample for the specified format or 0 if the format is unknown or not supported. This value is independent of whether the format is packed (interleaved) or planar (separate buffers per channel); it represents the size of one sample for a single channel.

Typical results are as follows: AV_SAMPLE_FMT_U8 and AV_SAMPLE_FMT_U8P yield 1 byte per sample; AV_SAMPLE_FMT_S16 and AV_SAMPLE_FMT_S16P yield 2 bytes; AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P, AV_SAMPLE_FMT_FLT, and AV_SAMPLE_FMT_FLTP yield 4 bytes; AV_SAMPLE_FMT_DBL and AV_SAMPLE_FMT_DBLP yield 8 bytes. For unsupported or unknown formats, the function returns 0.

In practice, the value is used to compute total buffer sizes. For example, total_bytes = frames_per_channel * channels * av_get_bytes_per_sample(fmt). When dealing with planar formats, buffers are separate per channel, but the per-sample byte size remains the same. The function is defined in libavutil/samplefmt.h and is complemented by related helpers such as av_get_bits_per_sample, which reports bits per sample for the same formats.