@@ -105,8 +105,8 @@ static const AVOption avcodec_options[] = {

 {"extradata_size", NULL, OFFSET(extradata_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},

 {"time_base", NULL, OFFSET(time_base), AV_OPT_TYPE_RATIONAL, {.dbl = 0}, INT_MIN, INT_MAX},

 {"g", "set the group of picture (GOP) size", OFFSET(gop_size), AV_OPT_TYPE_INT, {.i64 = 12 }, INT_MIN, INT_MAX, V|E},

-{"ar", "set audio sampling rate (in Hz)", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, A|D|E},

-{"ac", "set number of audio channels", OFFSET(channels), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, A|D|E},

+{"ar", "set audio sampling rate (in Hz)", OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, A|D|E},

+{"ac", "set number of audio channels", OFFSET(channels), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, A|D|E},

 {"cutoff", "set cutoff bandwidth", OFFSET(cutoff), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, A|E},

 {"frame_size", NULL, OFFSET(frame_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, A|E},

 {"frame_number", NULL, OFFSET(frame_number), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},