avcodec.h

     */
    int cutoff;

    /**
     * multiplied by qscale for each frame and added to scene_change_score
     * - encoding: set by user.
     * - decoding: unused
     */
    int scenechange_factor;

    /**
     *
     * note: value depends upon the compare functin used for fullpel ME
     * - encoding: set by user.
     * - decoding: unused
     */
    int mv0_threshold;

    /**
     * adjusts sensitivity of b_frame_strategy 1
     * - encoding: set by user.
     * - decoding: unused
     */
    int b_sensitivity;

    /**
     * - encoding: set by user.
     * - decoding: unused
     */
    int compression_level;
#define FF_COMPRESSION_DEFAULT -1

    /**
     * sets whether to use LPC mode - used by FLAC encoder
     * - encoding: set by user.
     * - decoding: unused.
     */
    int use_lpc;

    /**
     * LPC coefficient precision - used by FLAC encoder
     * - encoding: set by user.
     * - decoding: unused.
     */
    int lpc_coeff_precision;

    /**
     * - encoding: set by user.
     * - decoding: unused.
     */
    int min_prediction_order;

    /**
     * - encoding: set by user.
     * - decoding: unused.
     */
    int max_prediction_order;

    /**
     * search method for selecting prediction order
     * - encoding: set by user.
     * - decoding: unused.
     */
    int prediction_order_method;

    /**
     * - encoding: set by user.
     * - decoding: unused.
     */
    int min_partition_order;

    /**
     * - encoding: set by user.
     * - decoding: unused.
     */
    int max_partition_order;

    /**
     * GOP timecode frame start number, in non drop frame format
     * - encoding: set by user.
     * - decoding: unused.
     */
    int64_t timecode_frame_start;
} AVCodecContext;

/**
 * AVCodec.
 */
typedef struct AVCodec {
    const char *name;
    enum CodecType type;
    enum CodecID id;
    int priv_data_size;
    int (*init)(AVCodecContext *);
    int (*encode)(AVCodecContext *, uint8_t *buf, int buf_size, void *data);
    int (*close)(AVCodecContext *);
    int (*decode)(AVCodecContext *, void *outdata, int *outdata_size,
                  uint8_t *buf, int buf_size);
    int capabilities;
    struct AVCodec *next;
    void (*flush)(AVCodecContext *);
    const AVRational *supported_framerates; ///array of supported framerates, or NULL if any, array is terminated by {0,0}
    const enum PixelFormat *pix_fmts;       ///array of supported pixel formats, or NULL if unknown, array is terminanted by -1
} AVCodec;

/**
 * four components are given, that's all.
 * the last component is alpha
 */
typedef struct AVPicture {
    uint8_t *data[4];
    int linesize[4];       ///< number of bytes per line
} AVPicture;

/**
 * AVPaletteControl
 * This structure defines a method for communicating palette changes
 * between and demuxer and a decoder.
 * this is totally broken, palette changes should be sent as AVPackets
 */
#define AVPALETTE_SIZE 1024
#define AVPALETTE_COUNT 256
typedef struct AVPaletteControl {

    /* demuxer sets this to 1 to indicate the palette has changed;
     * decoder resets to 0 */
    int palette_changed;

    /* 4-byte ARGB palette entries, stored in native byte order; note that
     * the individual palette components should be on a 8-bit scale; if
     * the palette data comes from a IBM VGA native format, the component
     * data is probably 6 bits in size and needs to be scaled */
    unsigned int palette[AVPALETTE_COUNT];

} AVPaletteControl attribute_deprecated;

typedef struct AVSubtitleRect {
    uint16_t x;
    uint16_t y;
    uint16_t w;
    uint16_t h;
    uint16_t nb_colors;
    int linesize;
    uint32_t *rgba_palette;
    uint8_t *bitmap;
} AVSubtitleRect;

typedef struct AVSubtitle {
    uint16_t format; /* 0 = graphics */
    uint32_t start_display_time; /* relative to packet pts, in ms */
    uint32_t end_display_time; /* relative to packet pts, in ms */
    uint32_t num_rects;
    AVSubtitleRect *rects;
} AVSubtitle;

extern AVCodec ac3_encoder;
extern AVCodec amr_nb_encoder;
extern AVCodec amr_wb_encoder;
extern AVCodec asv1_encoder;
extern AVCodec asv2_encoder;
extern AVCodec bmp_encoder;
extern AVCodec dvvideo_encoder;
extern AVCodec faac_encoder;
extern AVCodec ffv1_encoder;
extern AVCodec ffvhuff_encoder;
extern AVCodec flac_encoder;
extern AVCodec flashsv_encoder;
extern AVCodec flv_encoder;
extern AVCodec gif_encoder;
extern AVCodec h261_encoder;
extern AVCodec h263_encoder;
extern AVCodec h263p_encoder;
extern AVCodec h264_encoder;
extern AVCodec huffyuv_encoder;
extern AVCodec jpegls_encoder;
extern AVCodec libgsm_encoder;
extern AVCodec libgsm_ms_encoder;
extern AVCodec libtheora_encoder;
extern AVCodec ljpeg_encoder;
extern AVCodec mdec_encoder;
extern AVCodec mjpeg_encoder;
extern AVCodec mp2_encoder;
extern AVCodec mp3lame_encoder;
extern AVCodec mpeg1video_encoder;
extern AVCodec mpeg2video_encoder;
extern AVCodec mpeg4_encoder;
extern AVCodec msmpeg4v1_encoder;
extern AVCodec msmpeg4v2_encoder;
extern AVCodec msmpeg4v3_encoder;
extern AVCodec oggvorbis_encoder;
extern AVCodec pam_encoder;
extern AVCodec pbm_encoder;
extern AVCodec pgm_encoder;
extern AVCodec pgmyuv_encoder;
extern AVCodec png_encoder;
extern AVCodec ppm_encoder;
extern AVCodec rv10_encoder;
extern AVCodec rv20_encoder;
extern AVCodec snow_encoder;
extern AVCodec sonic_encoder;
extern AVCodec sonic_ls_encoder;
extern AVCodec svq1_encoder;
extern AVCodec vcr1_encoder;
extern AVCodec vorbis_encoder;
extern AVCodec wmav1_encoder;
extern AVCodec wmav2_encoder;
extern AVCodec wmv1_encoder;
extern AVCodec wmv2_encoder;
extern AVCodec x264_encoder;
extern AVCodec xvid_encoder;
extern AVCodec zlib_encoder;
extern AVCodec zmbv_encoder;

extern AVCodec aac_decoder;
extern AVCodec aasc_decoder;
extern AVCodec alac_decoder;
extern AVCodec amr_nb_decoder;
extern AVCodec amr_wb_decoder;
extern AVCodec asv1_decoder;
extern AVCodec asv2_decoder;
extern AVCodec avs_decoder;
extern AVCodec bmp_decoder;
extern AVCodec cavs_decoder;
extern AVCodec cinepak_decoder;
extern AVCodec cljr_decoder;
extern AVCodec cook_decoder;
extern AVCodec cscd_decoder;
extern AVCodec cyuv_decoder;
extern AVCodec dca_decoder;
extern AVCodec dsicinaudio_decoder;
extern AVCodec dsicinvideo_decoder;
extern AVCodec dvvideo_decoder;
extern AVCodec eightbps_decoder;
extern AVCodec ffv1_decoder;
extern AVCodec ffvhuff_decoder;
extern AVCodec flac_decoder;
extern AVCodec flashsv_decoder;
extern AVCodec flic_decoder;
extern AVCodec flv_decoder;
extern AVCodec fourxm_decoder;
extern AVCodec fraps_decoder;
extern AVCodec gif_decoder;
extern AVCodec h261_decoder;
extern AVCodec h263_decoder;
extern AVCodec h263i_decoder;
extern AVCodec h264_decoder;
extern AVCodec huffyuv_decoder;
extern AVCodec idcin_decoder;
extern AVCodec imc_decoder;
extern AVCodec indeo2_decoder;
extern AVCodec indeo3_decoder;
extern AVCodec interplay_dpcm_decoder;
extern AVCodec interplay_video_decoder;
extern AVCodec kmvc_decoder;
extern AVCodec libgsm_decoder;
extern AVCodec libgsm_ms_decoder;
extern AVCodec loco_decoder;
extern AVCodec mace3_decoder;
extern AVCodec mace6_decoder;
extern AVCodec mdec_decoder;
extern AVCodec mjpeg_decoder;
extern AVCodec mjpegb_decoder;
extern AVCodec mmvideo_decoder;
extern AVCodec mp2_decoder;
extern AVCodec mp3_decoder;
extern AVCodec mp3adu_decoder;
extern AVCodec mp3on4_decoder;
extern AVCodec mpc7_decoder;
extern AVCodec mpeg1video_decoder;
extern AVCodec mpeg2video_decoder;
extern AVCodec mpeg4_decoder;
extern AVCodec mpeg4aac_decoder;
extern AVCodec mpeg_xvmc_decoder;
extern AVCodec mpegvideo_decoder;
extern AVCodec msmpeg4v1_decoder;
extern AVCodec msmpeg4v2_decoder;
extern AVCodec msmpeg4v3_decoder;
extern AVCodec msrle_decoder;
extern AVCodec msvideo1_decoder;
extern AVCodec mszh_decoder;
extern AVCodec nuv_decoder;
extern AVCodec oggvorbis_decoder;
extern AVCodec png_decoder;
extern AVCodec qdm2_decoder;
extern AVCodec qdraw_decoder;
extern AVCodec qpeg_decoder;
extern AVCodec qtrle_decoder;
extern AVCodec ra_144_decoder;
extern AVCodec ra_288_decoder;
extern AVCodec roq_decoder;
extern AVCodec roq_dpcm_decoder;
extern AVCodec rpza_decoder;
extern AVCodec rv10_decoder;
extern AVCodec rv20_decoder;
extern AVCodec rv30_decoder;
extern AVCodec rv40_decoder;
extern AVCodec shorten_decoder;
extern AVCodec smackaud_decoder;
extern AVCodec smacker_decoder;
extern AVCodec smc_decoder;
extern AVCodec snow_decoder;
extern AVCodec sol_dpcm_decoder;
extern AVCodec sonic_decoder;
extern AVCodec sp5x_decoder;
extern AVCodec svq1_decoder;
extern AVCodec svq3_decoder;
extern AVCodec targa_decoder;
extern AVCodec theora_decoder;
extern AVCodec tiertexseqvideo_decoder;
extern AVCodec tiff_decoder;
extern AVCodec truemotion1_decoder;
extern AVCodec truemotion2_decoder;
extern AVCodec truespeech_decoder;
extern AVCodec tscc_decoder;
extern AVCodec tta_decoder;
extern AVCodec ulti_decoder;
extern AVCodec vc1_decoder;
extern AVCodec vcr1_decoder;
extern AVCodec vmdaudio_decoder;
extern AVCodec vmdvideo_decoder;
extern AVCodec vmnc_decoder;
extern AVCodec vorbis_decoder;
extern AVCodec vp3_decoder;
extern AVCodec vp5_decoder;
extern AVCodec vp6_decoder;
extern AVCodec vp6f_decoder;
extern AVCodec vqa_decoder;
extern AVCodec wavpack_decoder;
extern AVCodec wmav1_decoder;
extern AVCodec wmav2_decoder;
extern AVCodec wmv1_decoder;
extern AVCodec wmv2_decoder;
extern AVCodec wmv3_decoder;
extern AVCodec wnv1_decoder;
extern AVCodec ws_snd1_decoder;
extern AVCodec xan_dpcm_decoder;
extern AVCodec xan_wc3_decoder;
extern AVCodec xl_decoder;
extern AVCodec zlib_decoder;
extern AVCodec zmbv_decoder;

/* pcm codecs */
#define PCM_CODEC(id, name) \
extern AVCodec name ## _decoder; \
extern AVCodec name ## _encoder

PCM_CODEC(CODEC_ID_PCM_ALAW,    pcm_alaw);
PCM_CODEC(CODEC_ID_PCM_MULAW,   pcm_mulaw);
PCM_CODEC(CODEC_ID_PCM_S8,      pcm_s8);
PCM_CODEC(CODEC_ID_PCM_S16BE,   pcm_s16be);
PCM_CODEC(CODEC_ID_PCM_S16LE,   pcm_s16le);
PCM_CODEC(CODEC_ID_PCM_S24BE,   pcm_s24be);
PCM_CODEC(CODEC_ID_PCM_S24DAUD, pcm_s24daud);
PCM_CODEC(CODEC_ID_PCM_S24LE,   pcm_s24le);
PCM_CODEC(CODEC_ID_PCM_S32BE,   pcm_s32be);
PCM_CODEC(CODEC_ID_PCM_S32LE,   pcm_s32le);
PCM_CODEC(CODEC_ID_PCM_U8,      pcm_u8);
PCM_CODEC(CODEC_ID_PCM_U16BE,   pcm_u16be);
PCM_CODEC(CODEC_ID_PCM_U16LE,   pcm_u16le);
PCM_CODEC(CODEC_ID_PCM_U24BE,   pcm_u24be);
PCM_CODEC(CODEC_ID_PCM_U24LE,   pcm_u24le);
PCM_CODEC(CODEC_ID_PCM_U32BE,   pcm_u32be);
PCM_CODEC(CODEC_ID_PCM_U32LE,   pcm_u32le);

/* adpcm codecs */

PCM_CODEC(CODEC_ID_ADPCM_4XM,     adpcm_4xm);
PCM_CODEC(CODEC_ID_ADPCM_ADX,     adpcm_adx);
PCM_CODEC(CODEC_ID_ADPCM_CT,      adpcm_ct);
PCM_CODEC(CODEC_ID_ADPCM_EA,      adpcm_ea);
PCM_CODEC(CODEC_ID_ADPCM_G726,    adpcm_g726);
PCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
PCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
PCM_CODEC(CODEC_ID_ADPCM_IMA_QT,  adpcm_ima_qt);
PCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
PCM_CODEC(CODEC_ID_ADPCM_IMA_WS,  adpcm_ima_ws);
PCM_CODEC(CODEC_ID_ADPCM_MS,      adpcm_ms);
PCM_CODEC(CODEC_ID_ADPCM_SBPRO_2, adpcm_sbpro_2);
PCM_CODEC(CODEC_ID_ADPCM_SBPRO_3, adpcm_sbpro_3);
PCM_CODEC(CODEC_ID_ADPCM_SBPRO_4, adpcm_sbpro_4);
PCM_CODEC(CODEC_ID_ADPCM_SMJPEG,  adpcm_ima_smjpeg);
PCM_CODEC(CODEC_ID_ADPCM_SWF,     adpcm_swf);
PCM_CODEC(CODEC_ID_ADPCM_XA,      adpcm_xa);
PCM_CODEC(CODEC_ID_ADPCM_YAMAHA,  adpcm_yamaha);

#undef PCM_CODEC

/* dummy raw video codec */
extern AVCodec rawvideo_decoder;
extern AVCodec rawvideo_encoder;

/* the following codecs use external GPL libs */
extern AVCodec dts_decoder;
extern AVCodec liba52_decoder;

/* subtitles */
extern AVCodec dvbsub_decoder;
extern AVCodec dvbsub_encoder;
extern AVCodec dvdsub_decoder;
extern AVCodec dvdsub_encoder;

/* resample.c */

struct ReSampleContext;
struct AVResampleContext;

typedef struct ReSampleContext ReSampleContext;

ReSampleContext *audio_resample_init(int output_channels, int input_channels,
                                     int output_rate, int input_rate);
int audio_resample(ReSampleContext *s, short *output, short *input, int nb_samples);
void audio_resample_close(ReSampleContext *s);

struct AVResampleContext *av_resample_init(int out_rate, int in_rate, int filter_length, int log2_phase_count, int linear, double cutoff);
int av_resample(struct AVResampleContext *c, short *dst, short *src, int *consumed, int src_size, int dst_size, int update_ctx);
void av_resample_compensate(struct AVResampleContext *c, int sample_delta, int compensation_distance);
void av_resample_close(struct AVResampleContext *c);

#if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
/* YUV420 format is assumed ! */

struct ImgReSampleContext attribute_deprecated;

typedef struct ImgReSampleContext ImgReSampleContext attribute_deprecated;

attribute_deprecated ImgReSampleContext *img_resample_init(int output_width, int output_height,
                                      int input_width, int input_height);

attribute_deprecated ImgReSampleContext *img_resample_full_init(int owidth, int oheight,
                                      int iwidth, int iheight,
                                      int topBand, int bottomBand,
                                      int leftBand, int rightBand,
                                      int padtop, int padbottom,
                                      int padleft, int padright);


attribute_deprecated void img_resample(ImgReSampleContext *s,
                  AVPicture *output, const AVPicture *input);

attribute_deprecated void img_resample_close(ImgReSampleContext *s);

#endif

/**
 * Allocate memory for a picture.  Call avpicture_free to free it.
 *
 * @param picture the picture to be filled in.
 * @param pix_fmt the format of the picture.
 * @param width the width of the picture.
 * @param height the height of the picture.
 * @return Zero if successful, a negative value if not.
 */
int avpicture_alloc(AVPicture *picture, int pix_fmt, int width, int height);

/**
 * Free a picture previously allocated by avpicture_alloc().
 *
 * @param picture The AVPicture to be freed.
 */
void avpicture_free(AVPicture *picture);

/**
 * Fill in AVPicture's fields.
 * The fields of the given AVPicture are filled in by using the 'ptr' address
 * which points to the image data buffer. Depending on the specified picture
 * format, one or multiple image data pointers and line sizes will be set.
 * If a planar format is specified, several pointers will be set pointing to
 * the different picture planes and the line sizes of the different planes
 * will be stored in the lines_sizes array.
 *
 * @param picture AVPicture who's fields are to be filled in
 * @param ptr Buffer which will contain or contains the actual image data
 * @param pix_fmt The format in which the picture data is stored
 * @param width The width of the image in pixels
 * @param height The height of the image in pixels
 * @return Size of the image data in bytes.
 */
int avpicture_fill(AVPicture *picture, uint8_t *ptr,
                   int pix_fmt, int width, int height);
int avpicture_layout(const AVPicture* src, int pix_fmt, int width, int height,
                     unsigned char *dest, int dest_size);

/**
 * Calculate the size in bytes that a picture of the given width and height
 * would occupy if stored in the given picture format.
 *
 * @param pix_fmt The given picture format
 * @param width The width of the image
 * @param height The height of the image
 * @return Image data size in bytes
 */
int avpicture_get_size(int pix_fmt, int width, int height);
void avcodec_get_chroma_sub_sample(int pix_fmt, int *h_shift, int *v_shift);
const char *avcodec_get_pix_fmt_name(int pix_fmt);
void avcodec_set_dimensions(AVCodecContext *s, int width, int height);
enum PixelFormat avcodec_get_pix_fmt(const char* name);
unsigned int avcodec_pix_fmt_to_codec_tag(enum PixelFormat p);

#define FF_LOSS_RESOLUTION  0x0001 /* loss due to resolution change */
#define FF_LOSS_DEPTH       0x0002 /* loss due to color depth change */
#define FF_LOSS_COLORSPACE  0x0004 /* loss due to color space conversion */
#define FF_LOSS_ALPHA       0x0008 /* loss of alpha bits */
#define FF_LOSS_COLORQUANT  0x0010 /* loss due to color quantization */
#define FF_LOSS_CHROMA      0x0020 /* loss of chroma (e.g. rgb to gray conversion) */

/**
 * compute the loss when converting from a pixel format to another
 */
int avcodec_get_pix_fmt_loss(int dst_pix_fmt, int src_pix_fmt,
                             int has_alpha);

/**
 * find best pixel format to convert to. Return -1 if none found
 */
int avcodec_find_best_pix_fmt(int pix_fmt_mask, int src_pix_fmt,
                              int has_alpha, int *loss_ptr);

#define FF_ALPHA_TRANSP       0x0001 /* image has some totally transparent pixels */
#define FF_ALPHA_SEMI_TRANSP  0x0002 /* image has some transparent pixels */

/**
 * Tell if an image really has transparent alpha values.
 * @return ored mask of FF_ALPHA_xxx constants
 */
int img_get_alpha_info(const AVPicture *src,
                       int pix_fmt, int width, int height);

#if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
/* convert among pixel formats */
attribute_deprecated int img_convert(AVPicture *dst, int dst_pix_fmt,
                const AVPicture *src, int pix_fmt,
                int width, int height);
#endif

/* deinterlace a picture */
/* deinterlace - if not supported return -1 */
int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
                          int pix_fmt, int width, int height);

/* external high level API */

extern AVCodec *first_avcodec;

/* returns LIBAVCODEC_VERSION_INT constant */
unsigned avcodec_version(void);
/* returns LIBAVCODEC_BUILD constant */
unsigned avcodec_build(void);

/**
 * Initializes libavcodec.
 *
 * @warning This function \e must be called before any other libavcodec
 * function.
 */
void avcodec_init(void);

void register_avcodec(AVCodec *format);

/**
 * Finds an encoder with a matching codec ID.
 *
 * @param id CodecID of the requested encoder.
 * @return An encoder if one was found, NULL otherwise.
 */
AVCodec *avcodec_find_encoder(enum CodecID id);

/**
 * Finds an encoder with the specified name.
 *
 * @param name Name of the requested encoder.
 * @return An encoder if one was found, NULL otherwise.
 */
AVCodec *avcodec_find_encoder_by_name(const char *name);

/**
 * Finds a decoder with a matching codec ID.
 *
 * @param id CodecID of the requested decoder.
 * @return A decoder if one was found, NULL otherwise.
 */
AVCodec *avcodec_find_decoder(enum CodecID id);

/**
 * Finds an decoder with the specified name.
 *
 * @param name Name of the requested decoder.
 * @return A decoder if one was found, NULL otherwise.
 */
AVCodec *avcodec_find_decoder_by_name(const char *name);
void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode);

/**
 * Sets the fields of the given AVCodecContext to default values.
 *
 * @param s The AVCodecContext of which the fields should be set to default values.
 */
void avcodec_get_context_defaults(AVCodecContext *s);

/**
 * Allocates an AVCodecContext and sets its fields to default values.  The
 * resulting struct can be deallocated by simply calling av_free().
 *
 * @return An AVCodecContext filled with default values or NULL on failure.
 * @see avcodec_get_context_defaults
 */
AVCodecContext *avcodec_alloc_context(void);

/**
 * Sets the fields of the given AVFrame to default values.
 *
 * @param pic The AVFrame of which the fields should be set to default values.
 */
void avcodec_get_frame_defaults(AVFrame *pic);

/**
 * Allocates an AVFrame and sets its fields to default values.  The resulting
 * struct can be deallocated by simply calling av_free().
 *
 * @return An AVFrame filled with default values or NULL on failure.
 * @see avcodec_get_frame_defaults
 */
AVFrame *avcodec_alloc_frame(void);

int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic);
void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic);
int avcodec_default_reget_buffer(AVCodecContext *s, AVFrame *pic);
void avcodec_align_dimensions(AVCodecContext *s, int *width, int *height);

/**
 * Checks if the given dimension of a picture is valid, meaning that all
 * bytes of the picture can be addressed with a signed int.
 *
 * @param[in] w Width of the picture.
 * @param[in] h Height of the picture.
 * @return Zero if valid, a negative value if invalid.
 */
int avcodec_check_dimensions(void *av_log_ctx, unsigned int w, unsigned int h);
enum PixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum PixelFormat * fmt);

int avcodec_thread_init(AVCodecContext *s, int thread_count);
void avcodec_thread_free(AVCodecContext *s);
int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count);
int avcodec_default_execute(AVCodecContext *c, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count);
//FIXME func typedef

/**
 * Initializes the AVCodecContext to use the given AVCodec. Prior to using this
 * function the context has to be allocated.
 *
 * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
 * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
 * retrieving a codec.
 *
 * @warning This function is not thread save!
 *
 * @code
 * codec = avcodec_find_decoder(CODEC_ID_H264);
 * if (!codec)
 *     exit(1);
 *
 * context = avcodec_alloc_context();
 *
 * if (avcodec_open(context, codec) < 0)
 *     exit(1);
 * @endcode
 *
 * @param avctx The context which will be setup to use the given codec.
 * @param codec The codec to use within the context.
 * @return Zero on success, a negative value on error.
 * @see avcodec_alloc_context, avcodec_find_decoder, avcodec_find_encoder
 */
int avcodec_open(AVCodecContext *avctx, AVCodec *codec);

/**
 * @deprecated Use avcodec_decode_audio2() instead.
 */
attribute_deprecated int avcodec_decode_audio(AVCodecContext *avctx, int16_t *samples,
                         int *frame_size_ptr,
                         uint8_t *buf, int buf_size);

/**
 * Decodes an audio frame from \p buf into \p samples.
 * The avcodec_decode_audio2() function decodes a frame of audio from the input
 * buffer \p buf of size \p buf_size. To decode it, it makes use of the
 * audiocodec which was coupled with \p avctx using avcodec_open(). The
 * resulting decoded frame is stored in output buffer \p samples.  If no frame
 * could be decompressed, \p frame_size_ptr is zero. Otherwise, it is the
 * decompressed frame size in \e bytes.
 *
 * @warning You \e must set \p frame_size_ptr to the allocated size of the
 * output buffer before calling avcodec_decode_audio2().
 *
 * @warning The input buffer must be \c FF_INPUT_BUFFER_PADDING_SIZE larger than
 * the actual read bytes because some optimized bitstream readers read 32 or 64
 * bits at once and could read over the end.
 *
 * @warning The end of the input buffer \p buf should be set to 0 to ensure that
 * no overreading happens for damaged MPEG streams.
 *
 * @note You might have to align the input buffer \p buf and output buffer \p
 * samples. The alignment requirements depend on the CPU: on some CPUs it isn't
 * necessary at all, on others it won't work at all if not aligned and on others
 * it will work but it will have an impact on performance. In practice, the
 * bitstream should have 4 byte alignment at minimum and all sample data should
 * be 16 byte aligned unless the CPU doesn't need it (AltiVec and SSE do). If
 * the linesize is not a multiple of 16 then there's no sense in aligning the
 * start of the buffer to 16.
 *
 * @param avctx The codec context.
 * @param[out] samples The output buffer.
 * @param[in,out] frame_size_ptr The output buffer size in bytes.
 * @param[in] buf The input buffer.
 * @param[in] buf_size The input buffer size in bytes.
 * @return On error a negative value is returned, otherwise the number of bytes
 * used or zero if no frame could be decompressed.
 */
int avcodec_decode_audio2(AVCodecContext *avctx, int16_t *samples,
                         int *frame_size_ptr,
                         uint8_t *buf, int buf_size);

/**
 * Decodes a video frame from \p buf into \p picture.
 * The avcodec_decode_video() function decodes a frame of video from the input
 * buffer \p buf of size \p buf_size. To decode it, it makes use of the
 * videocodec which was coupled with \p avctx using avcodec_open(). The
 * resulting decoded frame is stored in \p picture.
 *
 * @warning The input buffer must be \c FF_INPUT_BUFFER_PADDING_SIZE larger than
 * the actual read bytes because some optimized bitstream readers read 32 or 64
 * bits at once and could read over the end.
 *
 * @warning The end of the input buffer \p buf should be set to 0 to ensure that
 * no overreading happens for damaged MPEG streams.
 *
 * @note You might have to align the input buffer \p buf and output buffer \p
 * samples. The alignment requirements depend on the CPU: on some CPUs it isn't
 * necessary at all, on others it won't work at all if not aligned and on others
 * it will work but it will have an impact on performance. In practice, the
 * bitstream should have 4 byte alignment at minimum and all sample data should
 * be 16 byte aligned unless the CPU doesn't need it (AltiVec and SSE do). If
 * the linesize is not a multiple of 16 then there's no sense in aligning the
 * start of the buffer to 16.
 *
 * @param avctx The codec context.
 * @param[out] picture The AVFrame in which the decoded video frame will be stored.
 * @param[in] buf The input buffer.
 * @param[in] buf_size The size of the input buffer in bytes.
 * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is non zero.
 * @return On error a negative value is returned, otherwise the number of bytes
 * used or zero if no frame could be decompressed.
 */
int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture,
                         int *got_picture_ptr,
                         uint8_t *buf, int buf_size);

/* decode a subtitle message. return -1 if error, otherwise return the
   *number of bytes used. If no subtitle could be decompressed,
   *got_sub_ptr is zero. Otherwise, the subtitle is stored in *sub. */
int avcodec_decode_subtitle(AVCodecContext *avctx, AVSubtitle *sub,
                            int *got_sub_ptr,
                            const uint8_t *buf, int buf_size);
int avcodec_parse_frame(AVCodecContext *avctx, uint8_t **pdata,
                        int *data_size_ptr,
                        uint8_t *buf, int buf_size);

/**
 * Encodes an audio frame from \p samples into \p buf.
 * The avcodec_encode_audio() function encodes a frame of audio from the input
 * buffer \p samples. To encode it, it makes use of the audiocodec which was
 * coupled with \p avctx using avcodec_open(). The resulting encoded frame is
 * stored in output buffer \p buf.
 *
 * @note The output buffer should be at least \c FF_MIN_BUFFER_SIZE bytes large.
 *
 * @param avctx The codec context.
 * @param[out] buf The output buffer.
 * @param[in] buf_size The output buffer size.
 * @param[in] samples The input buffer containing the samples.
 * @return On error a negative value is returned, on succes zero or the number
 * of bytes used from the input buffer.
 */
int avcodec_encode_audio(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                         const short *samples);

/**
 * Encodes a video frame from \p pict into \p buf.
 * The avcodec_encode_video() function encodes a frame of video from the input
 * \p pict. To encode it, it makes use of the videocodec which was coupled with
 * \p avctx using avcodec_open(). The resulting encoded bytes representing the
 * frame are stored in the output buffer \p buf. The input picture should be
 * stored using a specific format, namely \c avctx.pix_fmt.
 *
 * @param avctx The codec context.
 * @param[out] buf The output buffer for the bitstream of encoded frame.
 * @param[in] buf_size The size of the outputbuffer in bytes.
 * @param[in] pict The input picture to encode.
 * @return On error a negative value is returned, on success zero or the number
 * of bytes used from the input buffer.
 */
int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                         const AVFrame *pict);
int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
                            const AVSubtitle *sub);

int avcodec_close(AVCodecContext *avctx);

void avcodec_register_all(void);

/**
 * Flush buffers, should be called when seeking or when switching to a different stream.
 */
void avcodec_flush_buffers(AVCodecContext *avctx);

void avcodec_default_free_buffers(AVCodecContext *s);

/* misc useful functions */

/**
 * Returns a single letter to describe the given picture type \p pict_type.
 *
 * @param[in] pict_type The picture type.
 * @return A single character representing the picture type.
 */
char av_get_pict_type_char(int pict_type);

/**
 * Returns codec bits per sample.
 *
 * @param[in] codec_id The codec.
 * @return Number of bits per sample or zero if unknown for the given codec.
 */
int av_get_bits_per_sample(enum CodecID codec_id);

/* frame parsing */
typedef struct AVCodecParserContext {
    void *priv_data;
    struct AVCodecParser *parser;
    int64_t frame_offset; /* offset of the current frame */
    int64_t cur_offset; /* current offset
                           (incremented by each av_parser_parse()) */
    int64_t last_frame_offset; /* offset of the last frame */
    /* video info */
    int pict_type; /* XXX: put it back in AVCodecContext */
    int repeat_pict; /* XXX: put it back in AVCodecContext */
    int64_t pts;     /* pts of the current frame */
    int64_t dts;     /* dts of the current frame */

    /* private data */
    int64_t last_pts;
    int64_t last_dts;
    int fetch_timestamp;

#define AV_PARSER_PTS_NB 4
    int cur_frame_start_index;
    int64_t cur_frame_offset[AV_PARSER_PTS_NB];
    int64_t cur_frame_pts[AV_PARSER_PTS_NB];
    int64_t cur_frame_dts[AV_PARSER_PTS_NB];

    int flags;
#define PARSER_FLAG_COMPLETE_FRAMES           0x0001
} AVCodecParserContext;

typedef struct AVCodecParser {
    int codec_ids[5]; /* several codec IDs are permitted */
    int priv_data_size;
    int (*parser_init)(AVCodecParserContext *s);
    int (*parser_parse)(AVCodecParserContext *s,
                        AVCodecContext *avctx,
                        uint8_t **poutbuf, int *poutbuf_size,
                        const uint8_t *buf, int buf_size);
    void (*parser_close)(AVCodecParserContext *s);
    int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
    struct AVCodecParser *next;
} AVCodecParser;

extern AVCodecParser *av_first_parser;

void av_register_codec_parser(AVCodecParser *parser);
AVCodecParserContext *av_parser_init(int codec_id);
int av_parser_parse(AVCodecParserContext *s,
                    AVCodecContext *avctx,
                    uint8_t **poutbuf, int *poutbuf_size,
                    const uint8_t *buf, int buf_size,
                    int64_t pts, int64_t dts);
int av_parser_change(AVCodecParserContext *s,
                     AVCodecContext *avctx,
                     uint8_t **poutbuf, int *poutbuf_size,
                     const uint8_t *buf, int buf_size, int keyframe);
void av_parser_close(AVCodecParserContext *s);

extern AVCodecParser aac_parser;
extern AVCodecParser ac3_parser;
extern AVCodecParser cavsvideo_parser;
extern AVCodecParser dca_parser;
extern AVCodecParser dvbsub_parser;
extern AVCodecParser dvdsub_parser;
extern AVCodecParser h261_parser;
extern AVCodecParser h263_parser;
extern AVCodecParser h264_parser;
extern AVCodecParser mjpeg_parser;
extern AVCodecParser mpeg4video_parser;
extern AVCodecParser mpegaudio_parser;
extern AVCodecParser mpegvideo_parser;
extern AVCodecParser pnm_parser;
extern AVCodecParser vc1_parser;


typedef struct AVBitStreamFilterContext {
    void *priv_data;
    struct AVBitStreamFilter *filter;
    AVCodecParserContext *parser;
    struct AVBitStreamFilterContext *next;
} AVBitStreamFilterContext;


typedef struct AVBitStreamFilter {
    const char *name;
    int priv_data_size;
    int (*filter)(AVBitStreamFilterContext *bsfc,
                  AVCodecContext *avctx, const char *args,
                  uint8_t **poutbuf, int *poutbuf_size,
                  const uint8_t *buf, int buf_size, int keyframe);
    struct AVBitStreamFilter *next;
} AVBitStreamFilter;

extern AVBitStreamFilter *av_first_bitstream_filter;

void av_register_bitstream_filter(AVBitStreamFilter *bsf);
AVBitStreamFilterContext *av_bitstream_filter_init(const char *name);
int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
                               AVCodecContext *avctx, const char *args,
                               uint8_t **poutbuf, int *poutbuf_size,
                               const uint8_t *buf, int buf_size, int keyframe);
void av_bitstream_filter_close(AVBitStreamFilterContext *bsf);

extern AVBitStreamFilter dump_extradata_bsf;
extern AVBitStreamFilter remove_extradata_bsf;
extern AVBitStreamFilter noise_bsf;
extern AVBitStreamFilter mp3_header_compress_bsf;
extern AVBitStreamFilter mp3_header_decompress_bsf;
extern AVBitStreamFilter mjpega_dump_header_bsf;


/* memory */

/**
 * Reallocates the given block if it is not large enough, otherwise it
 * does nothing.
 *
 * @see av_realloc
 */
void *av_fast_realloc(void *ptr, unsigned int *size, unsigned int min_size);

/* for static data only */

/**
 * Frees all static arrays and reset their pointers to 0.
 * Call this function to release all statically allocated tables.
 */
void av_free_static(void);

/**
 * Allocation of static arrays.
 *
 * @warning Do not use for normal allocation.
 *
 * @param[in] size The amount of memory you need in bytes.
 * @return Block of memory of the requested size.
 */
void *av_mallocz_static(unsigned int size);

/**
 * Copy image 'src' to 'dst'.
 */
void img_copy(AVPicture *dst, const AVPicture *src,
              int pix_fmt, int width, int height);

/**
 * Crop image top and left side
 */
int img_crop(AVPicture *dst, const AVPicture *src,
             int pix_fmt, int top_band, int left_band);

/**
 * Pad image
 */
int img_pad(AVPicture *dst, const AVPicture *src, int height, int width, int pix_fmt,
            int padtop, int padbottom, int padleft, int padright, int *color);

extern unsigned int av_xiphlacing(unsigned char *s, unsigned int v);

/* error handling */
#if EINVAL > 0
#define AVERROR(e) (-(e)) /**< returns a negative error code from a POSIX error code, to return from library functions. */
#define AVUNERROR(e) (-(e)) /**< returns a POSIX error code from a library function error return value. */
#else
/* some platforms have E* and errno already negated. */
#define AVERROR(e) (e)
#define AVUNERROR(e) (e)
#endif