const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len) { const AVOption *o = av_opt_find(obj, name, NULL, 0, 0); void *dst; uint8_t *bin; int len, i; if (!o || o->offset<=0) return NULL; if (o->type != FF_OPT_TYPE_STRING && (!buf || !buf_len)) return NULL; dst= ((uint8_t*)obj) + o->offset; if (o_out) *o_out= o; switch (o->type) { case FF_OPT_TYPE_FLAGS: snprintf(buf, buf_len, "0x%08X",*(int *)dst);break; case FF_OPT_TYPE_INT: snprintf(buf, buf_len, "%d" , *(int *)dst);break; case FF_OPT_TYPE_INT64: snprintf(buf, buf_len, "%"PRId64, *(int64_t*)dst);break; case FF_OPT_TYPE_FLOAT: snprintf(buf, buf_len, "%f" , *(float *)dst);break; case FF_OPT_TYPE_DOUBLE: snprintf(buf, buf_len, "%f" , *(double *)dst);break; case FF_OPT_TYPE_RATIONAL: snprintf(buf, buf_len, "%d/%d", ((AVRational*)dst)->num, ((AVRational*)dst)->den);break; case FF_OPT_TYPE_STRING: return *(void**)dst; case FF_OPT_TYPE_BINARY: len = *(int*)(((uint8_t *)dst) + sizeof(uint8_t *)); if (len >= (buf_len + 1)/2) return NULL; bin = *(uint8_t**)dst; for (i = 0; i < len; i++) snprintf(buf + i*2, 3, "%02X", bin[i]); break; default: return NULL; } return buf; }