#define PARAM AV_OPT_FLAG_AUDIO_PARAM
static const AVOption options[]={
-{"ich", "input channel count", OFFSET( in.ch_count ), AV_OPT_TYPE_INT, {.dbl=2}, 0, SWR_CH_MAX, PARAM},
-{"och", "output channel count", OFFSET(out.ch_count ), AV_OPT_TYPE_INT, {.dbl=2}, 0, SWR_CH_MAX, PARAM},
-{"uch", "used channel count", OFFSET(used_ch_count ), AV_OPT_TYPE_INT, {.dbl=0}, 0, SWR_CH_MAX, PARAM},
-{"isr", "input sample rate" , OFFSET( in_sample_rate), AV_OPT_TYPE_INT, {.dbl=48000}, 1, INT_MAX, PARAM},
-{"osr", "output sample rate" , OFFSET(out_sample_rate), AV_OPT_TYPE_INT, {.dbl=48000}, 1, INT_MAX, PARAM},
-//{"ip" , "input planar" , OFFSET( in.planar ), AV_OPT_TYPE_INT, {.dbl=0}, 0, 1, PARAM},
-//{"op" , "output planar" , OFFSET(out.planar ), AV_OPT_TYPE_INT, {.dbl=0}, 0, 1, PARAM},
-{"isf", "input sample format", OFFSET( in_sample_fmt ), AV_OPT_TYPE_INT, {.dbl=AV_SAMPLE_FMT_S16}, 0, AV_SAMPLE_FMT_NB-1+256, PARAM},
-{"osf", "output sample format", OFFSET(out_sample_fmt ), AV_OPT_TYPE_INT, {.dbl=AV_SAMPLE_FMT_S16}, 0, AV_SAMPLE_FMT_NB-1+256, PARAM},
-{"tsf", "internal sample format", OFFSET(int_sample_fmt ), AV_OPT_TYPE_INT, {.dbl=AV_SAMPLE_FMT_NONE}, -1, AV_SAMPLE_FMT_FLT, },
-{"icl", "input channel layout" , OFFSET( in_ch_layout), AV_OPT_TYPE_INT64, {.dbl=0}, 0, INT64_MAX, PARAM, "channel_layout"},
-{"ocl", "output channel layout", OFFSET(out_ch_layout), AV_OPT_TYPE_INT64, {.dbl=0}, 0, INT64_MAX, PARAM, "channel_layout"},
-{"clev", "center mix level" , OFFSET(clev) , AV_OPT_TYPE_FLOAT, {.dbl=C_30DB}, 0, 4, PARAM},
-{"slev", "sourround mix level" , OFFSET(slev) , AV_OPT_TYPE_FLOAT, {.dbl=C_30DB}, 0, 4, PARAM},
-{"rmvol", "rematrix volume" , OFFSET(rematrix_volume), AV_OPT_TYPE_FLOAT, {.dbl=1.0}, -1000, 1000, PARAM},
-{"flags", NULL , OFFSET(flags) , AV_OPT_TYPE_FLAGS, {.dbl=0}, 0, UINT_MAX, PARAM, "flags"},
-{"swr_flags", NULL , OFFSET(flags) , AV_OPT_TYPE_FLAGS, {.dbl=0}, 0, UINT_MAX, PARAM, "flags"},
-{"res", "force resampling", 0, AV_OPT_TYPE_CONST, {.dbl=SWR_FLAG_RESAMPLE}, INT_MIN, INT_MAX, PARAM, "flags"},
-{"dither_scale" , "dither scale" , OFFSET(dither_scale ), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0, INT_MAX, PARAM},
-{"dither_method", "dither method" , OFFSET(dither_method), AV_OPT_TYPE_INT , {.dbl=0}, 0, SWR_DITHER_NB-1, PARAM, "dither_method"},
-{"rectangular", "rectangular dither", 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_RECTANGULAR}, INT_MIN, INT_MAX, PARAM, "dither_method"},
-{"triangular" , "triangular dither" , 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR }, INT_MIN, INT_MAX, PARAM, "dither_method"},
-{"triangular_hp" , "triangular dither with high pass" , 0, AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR_HIGHPASS }, INT_MIN, INT_MAX, PARAM, "dither_method"},
+{"ich" , "input channel count" , OFFSET( in.ch_count ), AV_OPT_TYPE_INT , {.dbl=2 }, 0 , SWR_CH_MAX, PARAM},
+{"och" , "output channel count" , OFFSET(out.ch_count ), AV_OPT_TYPE_INT , {.dbl=2 }, 0 , SWR_CH_MAX, PARAM},
+{"uch" , "used channel count" , OFFSET(used_ch_count ), AV_OPT_TYPE_INT , {.dbl=0 }, 0 , SWR_CH_MAX, PARAM},
+{"isr" , "input sample rate" , OFFSET( in_sample_rate), AV_OPT_TYPE_INT , {.dbl=48000 }, 1 , INT_MAX , PARAM},
+{"osr" , "output sample rate" , OFFSET(out_sample_rate), AV_OPT_TYPE_INT , {.dbl=48000 }, 1 , INT_MAX , PARAM},
+{"isf" , "input sample format" , OFFSET( in_sample_fmt ), AV_OPT_TYPE_INT , {.dbl=AV_SAMPLE_FMT_S16 }, 0 , AV_SAMPLE_FMT_NB-1+256, PARAM},
+{"osf" , "output sample format" , OFFSET(out_sample_fmt ), AV_OPT_TYPE_INT , {.dbl=AV_SAMPLE_FMT_S16 }, 0 , AV_SAMPLE_FMT_NB-1+256, PARAM},
+{"tsf" , "internal sample format" , OFFSET(int_sample_fmt ), AV_OPT_TYPE_INT , {.dbl=AV_SAMPLE_FMT_NONE }, -1 , AV_SAMPLE_FMT_FLT, PARAM},
+{"icl" , "input channel layout" , OFFSET( in_ch_layout ), AV_OPT_TYPE_INT64, {.dbl=0 }, 0 , INT64_MAX , PARAM, "channel_layout"},
+{"ocl" , "output channel layout" , OFFSET(out_ch_layout ), AV_OPT_TYPE_INT64, {.dbl=0 }, 0 , INT64_MAX , PARAM, "channel_layout"},
+{"clev" , "center mix level" , OFFSET(clev ), AV_OPT_TYPE_FLOAT, {.dbl=C_30DB }, 0 , 4 , PARAM},
+{"slev" , "sourround mix level" , OFFSET(slev ), AV_OPT_TYPE_FLOAT, {.dbl=C_30DB }, 0 , 4 , PARAM},
+{"rmvol" , "rematrix volume" , OFFSET(rematrix_volume), AV_OPT_TYPE_FLOAT, {.dbl=1.0 }, -1000 , 1000 , PARAM},
+{"flags" , NULL , OFFSET(flags ), AV_OPT_TYPE_FLAGS, {.dbl=0 }, 0 , UINT_MAX , PARAM, "flags"},
+{"swr_flags" , NULL , OFFSET(flags ), AV_OPT_TYPE_FLAGS, {.dbl=0 }, 0 , UINT_MAX , PARAM, "flags"},
+{"res" , "force resampling" , 0 , AV_OPT_TYPE_CONST, {.dbl=SWR_FLAG_RESAMPLE }, INT_MIN, INT_MAX , PARAM, "flags"},
+{"dither_scale" , "dither scale" , OFFSET(dither_scale ), AV_OPT_TYPE_FLOAT, {.dbl=1 }, 0 , INT_MAX , PARAM},
+{"dither_method" , "dither method" , OFFSET(dither_method ), AV_OPT_TYPE_INT , {.dbl=0 }, 0 , SWR_DITHER_NB-1, PARAM, "dither_method"},
+{"rectangular" , "rectangular dither" , 0 , AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_RECTANGULAR}, INT_MIN, INT_MAX , PARAM, "dither_method"},
+{"triangular" , "triangular dither" , 0 , AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR }, INT_MIN, INT_MAX , PARAM, "dither_method"},
+{"triangular_hp" , "triangular dither with high pass" , 0 , AV_OPT_TYPE_CONST, {.dbl=SWR_DITHER_TRIANGULAR_HIGHPASS }, INT_MIN, INT_MAX, PARAM, "dither_method"},
{0}
};