AVSAMPLEFMTS32P

AV_SAMPLE_FMT_S32P is an audio sample format value in FFmpeg’s libavutil that represents 32-bit signed integer samples stored in planar layout. In planar formats, each channel has its own separate memory plane, so for a stream with c channels there are c distinct buffers, each containing nb_samples samples. This is in contrast to the interleaved variant AV_SAMPLE_FMT_S32, where all channels’ samples are stored in a single buffer with alternating channel samples.

Each sample occupies 4 bytes, so a planar buffer requires nb_samples × 4 bytes per channel, and the total memory for all channels is nb_samples × nb_channels × 4 bytes. The planar arrangement can be advantageous for certain audio processing pipelines and SIMD-enabled operations that operate channel-by-channel, though it may incur higher memory management complexity elsewhere.

AV_SAMPLE_FMT_S32P is part of FFmpeg’s AVSampleFormat enumeration and is supported by core codecs, resamplers, and filters through libavcodec, libswresample, and related APIs. When handling frames, planar formats expose one data pointer per channel (plane) rather than a single interleaved data buffer. Developers may allocate planar buffers with utilities such as av_samples_alloc_array_and_samples and access per-channel data via data[i] for channel i.

Common alternatives include AV_SAMPLE_FMT_S32 (interleaved) and other planar formats like AV_SAMPLE_FMT_S16P for 16-bit samples. This format is chosen based on the target ecosystem’s requirements and the desired memory layout for processing.