avcodec.h

    AVC_OPEN_BY_NAME = 0xACA000,
    AVC_OPEN_BY_CODEC_ID,
    AVC_OPEN_BY_FOURCC,
    AVC_CLOSE,

    AVC_FLUSH,
    // pin - struct { uint8_t* src, uint_t src_size }
    // pout - struct { AVPicture* img, consumed_bytes,
    AVC_DECODE,
    // pin - struct { AVPicture* img, uint8_t* dest, uint_t dest_size }
    // pout - uint_t used_from_dest_size
    AVC_ENCODE, 

    // query/get video commands
    AVC_GET_VERSION = 0xACB000,
    AVC_GET_WIDTH,
    AVC_GET_HEIGHT,
    AVC_GET_DELAY,
    AVC_GET_QUANT_TABLE,
    // ...

    // query/get audio commands
    AVC_GET_FRAME_SIZE = 0xABC000,

    // maybe define some simple structure which
    // might be passed to the user - but they can't
    // contain any codec specific parts and these
    // calls are usualy necessary only few times

    // set video commands
    AVC_SET_WIDTH = 0xACD000,
    AVC_SET_HEIGHT,

    // set video encoding commands
    AVC_SET_FRAME_RATE = 0xACD800,
    AVC_SET_QUALITY,
    AVC_SET_HURRY_UP,

    // set audio commands
    AVC_SET_SAMPLE_RATE = 0xACE000,
    AVC_SET_CHANNELS,

} avc_cmd_t;

/**
 * \param handle  allocated private structure by libavcodec
 *                for initialization pass NULL - will be returned pout
 *                user is supposed to know nothing about its structure
 * \param cmd     type of operation to be performed
 * \param pint    input parameter
 * \param pout    output parameter
 *
 * \returns  command status - eventually for query command it might return
 * integer resulting value
 */
int avcodec(void* handle, avc_cmd_t cmd, void* pin, void* pout);

/* memory */
void *av_malloc(unsigned int size);
void *av_mallocz(unsigned int size);
void av_free(void *ptr);
void __av_freep(void **ptr);
#define av_freep(p) __av_freep((void **)(p))
/* for static data only */
/* call av_free_static to release all staticaly allocated tables */
void av_free_static();
void *__av_mallocz_static(void** location, unsigned int size);
#define av_mallocz_static(p, s) __av_mallocz_static((void **)(p), s)

#endif /* AVCODEC_H */