AVSAMPLEFMTU8P

AV_SAMPLE_FMT_U8P is an FFmpeg sample format enum value representing planar 8-bit unsigned PCM audio. It denotes a data layout in which the samples for each channel are stored in separate buffers (one buffer per channel) rather than being interleaved in a single packed buffer.

In memory, a frame with N samples per channel and C channels would consist of C distinct buffers, each containing N bytes. This planar arrangement can simplify per-channel processing and parallelization, especially in resampling, filtering, or channel-specific effects. By contrast, packed formats interleave samples from all channels in one contiguous buffer.

Technical characteristics include that each sample occupies one byte and the data values range from 0 to 255. Because the data is unsigned, a mid-scale value is used to represent silence (commonly 128 in practical applications). This contrasts with signed formats (where zero represents silence) and with floating-point formats that use a continuous range.

Usage and interoperability: AV_SAMPLE_FMT_U8P is part of the AVSampleFormat enum defined in FFmpeg’s libavutil. It is recognized by decoding, encoding, and resampling components, such as libavcodec and libswresample. Helpers in FFmpeg, such as av_sample_fmt_is_planar(fmt) and av_get_bytes_per_sample(fmt), assist in querying layout and size. The av_get_sample_fmt_name(fmt) function returns a short string like "u8p" for this format.

Notes: 8-bit unsigned planar PCM is less common for modern high-fidelity audio, where signed or floating-point formats are prevalent. When processing or transporting audio, developers may convert to a more widely supported format (e.g., s16 or f32) depending on the pipeline requirements.