filters实现设置音频的AV_SAMPLE_FMT_S16P

enum AVSampleFormat {
    AV_SAMPLE_FMT_NONE = -1,
    AV_SAMPLE_FMT_U8,          ///< unsigned 8 bits
    AV_SAMPLE_FMT_S16,         ///< signed 16 bits
    AV_SAMPLE_FMT_S32,         ///< signed 32 bits
    AV_SAMPLE_FMT_FLT,         ///< float
    AV_SAMPLE_FMT_DBL,         ///< double


    AV_SAMPLE_FMT_U8P,         ///< unsigned 8 bits, planar
    AV_SAMPLE_FMT_S16P,        ///< signed 16 bits, planar
    AV_SAMPLE_FMT_S32P,        ///< signed 32 bits, planar
    AV_SAMPLE_FMT_FLTP,        ///< float, planar
    AV_SAMPLE_FMT_DBLP,        ///< double, planar

    AV_SAMPLE_FMT_NB           ///< Number of sample formats. DO NOT USE if linking dynamically
};

6.6 aformat

Set output format constraints for the input audio. The framework will negotiate the most appropriate format to minimize conversions.

The filter accepts the following named parameters:

‘ sample_fmts’

A ’|’-separated list of requested sample formats.

‘ sample_rates’

A ’|’-separated list of requested sample rates.

‘ channel_layouts’

A ’|’-separated list of requested channel layouts.

See (ffmpeg-utils)channel layout syntax for the required syntax.

If a parameter is omitted, all values are allowed.

For example to force the output to either unsigned 8-bit or signed 16-bit stereo:

<span style="font-family:Arial, Helvetica, sans-serif;color:#000000;"><span style="white-space: normal;">aformat=sample_fmts=u8|s16:channel_layouts=stereo </span></span>