virtual_oss_compressor
struct virtual_oss_compressor out_lim;
#define VIRTUAL_OSS_SET_OUTPUT_LIMIT _IOW('O', 17, struct virtual_oss_compressor)
#define VIRTUAL_OSS_GET_OUTPUT_LIMIT _IOWR('O', 18, struct virtual_oss_compressor)
struct virtual_oss_compressor param;