avcodec.h

/*
 * copyright (c) 2001 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef AVCODEC_H
#define AVCODEC_H

/**
 * @file avcodec.h
 * external api header.
 */


#ifdef __cplusplus
extern "C" {
#endif

#include "avutil.h"
#include <sys/types.h> /* size_t */

#define AV_STRINGIFY(s)         AV_TOSTRING(s)
#define AV_TOSTRING(s) #s

#define LIBAVCODEC_VERSION_INT  ((51<<16)+(34<<8)+0)
#define LIBAVCODEC_VERSION      51.34.0
#define LIBAVCODEC_BUILD        LIBAVCODEC_VERSION_INT

#define LIBAVCODEC_IDENT        "Lavc" AV_STRINGIFY(LIBAVCODEC_VERSION)

#define AV_NOPTS_VALUE          INT64_C(0x8000000000000000)
#define AV_TIME_BASE            1000000
#define AV_TIME_BASE_Q          (AVRational){1, AV_TIME_BASE}

enum CodecID {
    CODEC_ID_NONE,
    CODEC_ID_MPEG1VIDEO,
    CODEC_ID_MPEG2VIDEO, /* prefered ID for MPEG Video 1 or 2 decoding */
    CODEC_ID_MPEG2VIDEO_XVMC,
    CODEC_ID_H261,
    CODEC_ID_H263,
    CODEC_ID_RV10,
    CODEC_ID_RV20,
    CODEC_ID_MJPEG,
    CODEC_ID_MJPEGB,
    CODEC_ID_LJPEG,
    CODEC_ID_SP5X,
    CODEC_ID_JPEGLS,
    CODEC_ID_MPEG4,
    CODEC_ID_RAWVIDEO,
    CODEC_ID_MSMPEG4V1,
    CODEC_ID_MSMPEG4V2,
    CODEC_ID_MSMPEG4V3,
    CODEC_ID_WMV1,
    CODEC_ID_WMV2,
    CODEC_ID_H263P,
    CODEC_ID_H263I,
    CODEC_ID_FLV1,
    CODEC_ID_SVQ1,
    CODEC_ID_SVQ3,
    CODEC_ID_DVVIDEO,
    CODEC_ID_HUFFYUV,
    CODEC_ID_CYUV,
    CODEC_ID_H264,
    CODEC_ID_INDEO3,
    CODEC_ID_VP3,
    CODEC_ID_THEORA,
    CODEC_ID_ASV1,
    CODEC_ID_ASV2,
    CODEC_ID_FFV1,
    CODEC_ID_4XM,
    CODEC_ID_VCR1,
    CODEC_ID_CLJR,
    CODEC_ID_MDEC,
    CODEC_ID_ROQ,
    CODEC_ID_INTERPLAY_VIDEO,
    CODEC_ID_XAN_WC3,
    CODEC_ID_XAN_WC4,
    CODEC_ID_RPZA,
    CODEC_ID_CINEPAK,
    CODEC_ID_WS_VQA,
    CODEC_ID_MSRLE,
    CODEC_ID_MSVIDEO1,
    CODEC_ID_IDCIN,
    CODEC_ID_8BPS,
    CODEC_ID_SMC,
    CODEC_ID_FLIC,
    CODEC_ID_TRUEMOTION1,
    CODEC_ID_VMDVIDEO,
    CODEC_ID_MSZH,
    CODEC_ID_ZLIB,
    CODEC_ID_QTRLE,
    CODEC_ID_SNOW,
    CODEC_ID_TSCC,
    CODEC_ID_ULTI,
    CODEC_ID_QDRAW,
    CODEC_ID_VIXL,
    CODEC_ID_QPEG,
    CODEC_ID_XVID,
    CODEC_ID_PNG,
    CODEC_ID_PPM,
    CODEC_ID_PBM,
    CODEC_ID_PGM,
    CODEC_ID_PGMYUV,
    CODEC_ID_PAM,
    CODEC_ID_FFVHUFF,
    CODEC_ID_RV30,
    CODEC_ID_RV40,
    CODEC_ID_VC1,
    CODEC_ID_WMV3,
    CODEC_ID_LOCO,
    CODEC_ID_WNV1,
    CODEC_ID_AASC,
    CODEC_ID_INDEO2,
    CODEC_ID_FRAPS,
    CODEC_ID_TRUEMOTION2,
    CODEC_ID_BMP,
    CODEC_ID_CSCD,
    CODEC_ID_MMVIDEO,
    CODEC_ID_ZMBV,
    CODEC_ID_AVS,
    CODEC_ID_SMACKVIDEO,
    CODEC_ID_NUV,
    CODEC_ID_KMVC,
    CODEC_ID_FLASHSV,
    CODEC_ID_CAVS,
    CODEC_ID_JPEG2000,
    CODEC_ID_VMNC,
    CODEC_ID_VP5,
    CODEC_ID_VP6,
    CODEC_ID_VP6F,
    CODEC_ID_TARGA,
    CODEC_ID_DSICINVIDEO,
    CODEC_ID_TIERTEXSEQVIDEO,
    CODEC_ID_TIFF,
    CODEC_ID_GIF,
    CODEC_ID_FFH264,

    /* various pcm "codecs" */
    CODEC_ID_PCM_S16LE= 0x10000,
    CODEC_ID_PCM_S16BE,
    CODEC_ID_PCM_U16LE,
    CODEC_ID_PCM_U16BE,
    CODEC_ID_PCM_S8,
    CODEC_ID_PCM_U8,
    CODEC_ID_PCM_MULAW,
    CODEC_ID_PCM_ALAW,
    CODEC_ID_PCM_S32LE,
    CODEC_ID_PCM_S32BE,
    CODEC_ID_PCM_U32LE,
    CODEC_ID_PCM_U32BE,
    CODEC_ID_PCM_S24LE,
    CODEC_ID_PCM_S24BE,
    CODEC_ID_PCM_U24LE,
    CODEC_ID_PCM_U24BE,
    CODEC_ID_PCM_S24DAUD,

    /* various adpcm codecs */
    CODEC_ID_ADPCM_IMA_QT= 0x11000,
    CODEC_ID_ADPCM_IMA_WAV,
    CODEC_ID_ADPCM_IMA_DK3,
    CODEC_ID_ADPCM_IMA_DK4,
    CODEC_ID_ADPCM_IMA_WS,
    CODEC_ID_ADPCM_IMA_SMJPEG,
    CODEC_ID_ADPCM_MS,
    CODEC_ID_ADPCM_4XM,
    CODEC_ID_ADPCM_XA,
    CODEC_ID_ADPCM_ADX,
    CODEC_ID_ADPCM_EA,
    CODEC_ID_ADPCM_G726,
    CODEC_ID_ADPCM_CT,
    CODEC_ID_ADPCM_SWF,
    CODEC_ID_ADPCM_YAMAHA,
    CODEC_ID_ADPCM_SBPRO_4,
    CODEC_ID_ADPCM_SBPRO_3,
    CODEC_ID_ADPCM_SBPRO_2,

    /* AMR */
    CODEC_ID_AMR_NB= 0x12000,
    CODEC_ID_AMR_WB,

    /* RealAudio codecs*/
    CODEC_ID_RA_144= 0x13000,
    CODEC_ID_RA_288,

    /* various DPCM codecs */
    CODEC_ID_ROQ_DPCM= 0x14000,
    CODEC_ID_INTERPLAY_DPCM,
    CODEC_ID_XAN_DPCM,
    CODEC_ID_SOL_DPCM,

    CODEC_ID_MP2= 0x15000,
    CODEC_ID_MP3, /* prefered ID for MPEG Audio layer 1, 2 or3 decoding */
    CODEC_ID_AAC,
#if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
    CODEC_ID_MPEG4AAC,
#endif
    CODEC_ID_AC3,
    CODEC_ID_DTS,
    CODEC_ID_VORBIS,
    CODEC_ID_DVAUDIO,
    CODEC_ID_WMAV1,
    CODEC_ID_WMAV2,
    CODEC_ID_MACE3,
    CODEC_ID_MACE6,
    CODEC_ID_VMDAUDIO,
    CODEC_ID_SONIC,
    CODEC_ID_SONIC_LS,
    CODEC_ID_FLAC,
    CODEC_ID_MP3ADU,
    CODEC_ID_MP3ON4,
    CODEC_ID_SHORTEN,
    CODEC_ID_ALAC,
    CODEC_ID_WESTWOOD_SND1,
    CODEC_ID_GSM, /* As in Berlin toast format */
    CODEC_ID_QDM2,
    CODEC_ID_COOK,
    CODEC_ID_TRUESPEECH,
    CODEC_ID_TTA,
    CODEC_ID_SMACKAUDIO,
    CODEC_ID_QCELP,
    CODEC_ID_WAVPACK,
    CODEC_ID_DSICINAUDIO,
    CODEC_ID_IMC,
    CODEC_ID_MUSEPACK7,
    CODEC_ID_MLP,
    CODEC_ID_GSM_MS, /* As found in WAV */

    /* subtitle codecs */
    CODEC_ID_DVD_SUBTITLE= 0x17000,
    CODEC_ID_DVB_SUBTITLE,

    CODEC_ID_MPEG2TS= 0x20000, /* _FAKE_ codec to indicate a raw MPEG2 transport
                         stream (only used by libavformat) */
};

/* CODEC_ID_MP3LAME is absolete */
#define CODEC_ID_MP3LAME CODEC_ID_MP3

enum CodecType {
    CODEC_TYPE_UNKNOWN = -1,
    CODEC_TYPE_VIDEO,
    CODEC_TYPE_AUDIO,
    CODEC_TYPE_DATA,
    CODEC_TYPE_SUBTITLE,
};

/* currently unused, may be used if 24/32 bits samples ever supported */
/* all in native endian */
enum SampleFormat {
    SAMPLE_FMT_NONE = -1,
    SAMPLE_FMT_U8,              ///< unsigned 8 bits
    SAMPLE_FMT_S16,             ///< signed 16 bits
    SAMPLE_FMT_S24,             ///< signed 24 bits
    SAMPLE_FMT_S32,             ///< signed 32 bits
    SAMPLE_FMT_FLT,             ///< float
};

/* in bytes */
#define AVCODEC_MAX_AUDIO_FRAME_SIZE 192000 // 1 second of 48khz 32bit audio

/**
 * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
 * this is mainly needed because some optimized bitstream readers read
 * 32 or 64 bit at once and could read over the end<br>
 * Note, if the first 23 bits of the additional bytes are not 0 then damaged
 * MPEG bitstreams could cause overread and segfault
 */
#define FF_INPUT_BUFFER_PADDING_SIZE 8

/**
 * minimum encoding buffer size.
 * used to avoid some checks during header writing
 */
#define FF_MIN_BUFFER_SIZE 16384

/* motion estimation type, EPZS by default */
enum Motion_Est_ID {
    ME_ZERO = 1,
    ME_FULL,
    ME_LOG,
    ME_PHODS,
    ME_EPZS,
    ME_X1,
    ME_HEX,
    ME_UMH,
    ME_ITER,
};

enum AVDiscard{
//we leave some space between them for extensions (drop some keyframes for intra only or drop just some bidir frames)
    AVDISCARD_NONE   =-16, ///< discard nothing
    AVDISCARD_DEFAULT=  0, ///< discard useless packets like 0 size packets in avi
    AVDISCARD_NONREF =  8, ///< discard all non reference
    AVDISCARD_BIDIR  = 16, ///< discard all bidirectional frames
    AVDISCARD_NONKEY = 32, ///< discard all frames except keyframes
    AVDISCARD_ALL    = 48, ///< discard all
};

typedef struct RcOverride{
    int start_frame;
    int end_frame;
    int qscale; // if this is 0 then quality_factor will be used instead
    float quality_factor;
} RcOverride;

#define FF_MAX_B_FRAMES 16

/* encoding support
   these flags can be passed in AVCodecContext.flags before initing
   Note: not everything is supported yet.
*/

#define CODEC_FLAG_QSCALE 0x0002  ///< use fixed qscale
#define CODEC_FLAG_4MV    0x0004  ///< 4 MV per MB allowed / Advanced prediction for H263
#define CODEC_FLAG_QPEL   0x0010  ///< use qpel MC
#define CODEC_FLAG_GMC    0x0020  ///< use GMC
#define CODEC_FLAG_MV0    0x0040  ///< always try a MB with MV=<0,0>
#define CODEC_FLAG_PART   0x0080  ///< use data partitioning
/* parent program guarantees that the input for b-frame containing streams is not written to
   for at least s->max_b_frames+1 frames, if this is not set than the input will be copied */
#define CODEC_FLAG_INPUT_PRESERVED 0x0100
#define CODEC_FLAG_PASS1 0x0200   ///< use internal 2pass ratecontrol in first  pass mode
#define CODEC_FLAG_PASS2 0x0400   ///< use internal 2pass ratecontrol in second pass mode
#define CODEC_FLAG_EXTERN_HUFF 0x1000 ///< use external huffman table (for mjpeg)
#define CODEC_FLAG_GRAY  0x2000   ///< only decode/encode grayscale
#define CODEC_FLAG_EMU_EDGE 0x4000///< don't draw edges
#define CODEC_FLAG_PSNR           0x8000 ///< error[?] variables will be set during encoding
#define CODEC_FLAG_TRUNCATED  0x00010000 /** input bitstream might be truncated at a random location instead
                                            of only at frame boundaries */
#define CODEC_FLAG_NORMALIZE_AQP  0x00020000 ///< normalize adaptive quantization
#define CODEC_FLAG_INTERLACED_DCT 0x00040000 ///< use interlaced dct
#define CODEC_FLAG_LOW_DELAY      0x00080000 ///< force low delay
#define CODEC_FLAG_ALT_SCAN       0x00100000 ///< use alternate scan
#define CODEC_FLAG_TRELLIS_QUANT  0x00200000 ///< use trellis quantization
#define CODEC_FLAG_GLOBAL_HEADER  0x00400000 ///< place global headers in extradata instead of every keyframe
#define CODEC_FLAG_BITEXACT       0x00800000 ///< use only bitexact stuff (except (i)dct)
/* Fx : Flag for h263+ extra options */
#define CODEC_FLAG_H263P_AIC      0x01000000 ///< H263 Advanced intra coding / MPEG4 AC prediction (remove this)
#define CODEC_FLAG_AC_PRED        0x01000000 ///< H263 Advanced intra coding / MPEG4 AC prediction
#define CODEC_FLAG_H263P_UMV      0x02000000 ///< Unlimited motion vector
#define CODEC_FLAG_CBP_RD         0x04000000 ///< use rate distortion optimization for cbp
#define CODEC_FLAG_QP_RD          0x08000000 ///< use rate distortion optimization for qp selectioon
#define CODEC_FLAG_H263P_AIV      0x00000008 ///< H263 Alternative inter vlc
#define CODEC_FLAG_OBMC           0x00000001 ///< OBMC
#define CODEC_FLAG_LOOP_FILTER    0x00000800 ///< loop filter
#define CODEC_FLAG_H263P_SLICE_STRUCT 0x10000000
#define CODEC_FLAG_INTERLACED_ME  0x20000000 ///< interlaced motion estimation
#define CODEC_FLAG_SVCD_SCAN_OFFSET 0x40000000 ///< will reserve space for SVCD scan offset user data
#define CODEC_FLAG_CLOSED_GOP     ((int)0x80000000)
#define CODEC_FLAG2_FAST          0x00000001 ///< allow non spec compliant speedup tricks
#define CODEC_FLAG2_STRICT_GOP    0x00000002 ///< strictly enforce GOP size
#define CODEC_FLAG2_NO_OUTPUT     0x00000004 ///< skip bitstream encoding
#define CODEC_FLAG2_LOCAL_HEADER  0x00000008 ///< place global headers at every keyframe instead of in extradata
#define CODEC_FLAG2_BPYRAMID      0x00000010 ///< H.264 allow b-frames to be used as references
#define CODEC_FLAG2_WPRED         0x00000020 ///< H.264 weighted biprediction for b-frames
#define CODEC_FLAG2_MIXED_REFS    0x00000040 ///< H.264 one reference per partition, as opposed to one reference per macroblock
#define CODEC_FLAG2_8X8DCT        0x00000080 ///< H.264 high profile 8x8 transform
#define CODEC_FLAG2_FASTPSKIP     0x00000100 ///< H.264 fast pskip
#define CODEC_FLAG2_AUD           0x00000200 ///< H.264 access unit delimiters
#define CODEC_FLAG2_BRDO          0x00000400 ///< b-frame rate-distortion optimization
#define CODEC_FLAG2_INTRA_VLC     0x00000800 ///< use MPEG-2 intra VLC table
#define CODEC_FLAG2_MEMC_ONLY     0x00001000 ///< only do ME/MC (I frames -> ref, P frame -> ME+MC)
#define CODEC_FLAG2_DROP_FRAME_TIMECODE 0x00002000 ///< timecode is in drop frame format
#define CODEC_FLAG2_SKIP_RD       0x00004000 ///< RD optimal MB level residual skiping

/* Unsupported options :
 *              Syntax Arithmetic coding (SAC)
 *              Reference Picture Selection
 *              Independant Segment Decoding */
/* /Fx */
/* codec capabilities */

#define CODEC_CAP_DRAW_HORIZ_BAND 0x0001 ///< decoder can use draw_horiz_band callback
/**
 * Codec uses get_buffer() for allocating buffers.
 * direct rendering method 1
 */
#define CODEC_CAP_DR1             0x0002
/* if 'parse_only' field is true, then avcodec_parse_frame() can be
   used */
#define CODEC_CAP_PARSE_ONLY      0x0004
#define CODEC_CAP_TRUNCATED       0x0008
/* codec can export data for HW decoding (XvMC) */
#define CODEC_CAP_HWACCEL         0x0010
/**
 * codec has a non zero delay and needs to be feeded with NULL at the end to get the delayed data.
 * if this is not set, the codec is guaranteed to never be feeded with NULL data
 */
#define CODEC_CAP_DELAY           0x0020
/**
 * Codec can be fed a final frame with a smaller size.
 * This can be used to prevent truncation of the last audio samples.
 */
#define CODEC_CAP_SMALL_LAST_FRAME 0x0040

//the following defines may change, don't expect compatibility if you use them
#define MB_TYPE_INTRA4x4   0x0001
#define MB_TYPE_INTRA16x16 0x0002 //FIXME h264 specific
#define MB_TYPE_INTRA_PCM  0x0004 //FIXME h264 specific
#define MB_TYPE_16x16      0x0008
#define MB_TYPE_16x8       0x0010
#define MB_TYPE_8x16       0x0020
#define MB_TYPE_8x8        0x0040
#define MB_TYPE_INTERLACED 0x0080
#define MB_TYPE_DIRECT2     0x0100 //FIXME
#define MB_TYPE_ACPRED     0x0200
#define MB_TYPE_GMC        0x0400
#define MB_TYPE_SKIP       0x0800
#define MB_TYPE_P0L0       0x1000
#define MB_TYPE_P1L0       0x2000
#define MB_TYPE_P0L1       0x4000
#define MB_TYPE_P1L1       0x8000
#define MB_TYPE_L0         (MB_TYPE_P0L0 | MB_TYPE_P1L0)
#define MB_TYPE_L1         (MB_TYPE_P0L1 | MB_TYPE_P1L1)
#define MB_TYPE_L0L1       (MB_TYPE_L0   | MB_TYPE_L1)
#define MB_TYPE_QUANT      0x00010000
#define MB_TYPE_CBP        0x00020000
//Note bits 24-31 are reserved for codec specific use (h264 ref0, mpeg1 0mv, ...)

/**
 * Pan Scan area.
 * this specifies the area which should be displayed. Note there may be multiple such areas for one frame
 */
typedef struct AVPanScan{
    /**
     * id.
     * - encoding: set by user.
     * - decoding: set by lavc
     */
    int id;

    /**
     * width and height in 1/16 pel
     * - encoding: set by user.
     * - decoding: set by lavc
     */
    int width;
    int height;

    /**
     * position of the top left corner in 1/16 pel for up to 3 fields/frames.
     * - encoding: set by user.
     * - decoding: set by lavc
     */
    int16_t position[3][2];
}AVPanScan;

#define FF_COMMON_FRAME \
    /**\
     * pointer to the picture planes.\
     * this might be different from the first allocated byte\
     * - encoding: \
     * - decoding: \
     */\
    uint8_t *data[4];\
    int linesize[4];\
    /**\
     * pointer to the first allocated byte of the picture. can be used in get_buffer/release_buffer\
     * this isn't used by lavc unless the default get/release_buffer() is used\
     * - encoding: \
     * - decoding: \
     */\
    uint8_t *base[4];\
    /**\
     * 1 -> keyframe, 0-> not\
     * - encoding: set by lavc\
     * - decoding: set by lavc\
     */\
    int key_frame;\
\
    /**\
     * picture type of the frame, see ?_TYPE below.\
     * - encoding: set by lavc for coded_picture (and set by user for input)\
     * - decoding: set by lavc\
     */\
    int pict_type;\
\
    /**\
     * presentation timestamp in time_base units (time when frame should be shown to user)\
     * if AV_NOPTS_VALUE then frame_rate = 1/time_base will be assumed\
     * - encoding: MUST be set by user\
     * - decoding: set by lavc\
     */\
    int64_t pts;\
\
    /**\
     * picture number in bitstream order.\
     * - encoding: set by\
     * - decoding: set by lavc\
     */\
    int coded_picture_number;\
    /**\
     * picture number in display order.\
     * - encoding: set by\
     * - decoding: set by lavc\
     */\
    int display_picture_number;\
\
    /**\
     * quality (between 1 (good) and FF_LAMBDA_MAX (bad)) \
     * - encoding: set by lavc for coded_picture (and set by user for input)\
     * - decoding: set by lavc\
     */\
    int quality; \
\
    /**\
     * buffer age (1->was last buffer and dint change, 2->..., ...).\
     * set to INT_MAX if the buffer has not been used yet \
     * - encoding: unused\
     * - decoding: MUST be set by get_buffer()\
     */\
    int age;\
\
    /**\
     * is this picture used as reference\
     * - encoding: unused\
     * - decoding: set by lavc (before get_buffer() call))\
     */\
    int reference;\
\
    /**\
     * QP table\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    int8_t *qscale_table;\
    /**\
     * QP store stride\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    int qstride;\
\
    /**\
     * mbskip_table[mb]>=1 if MB didnt change\
     * stride= mb_width = (width+15)>>4\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    uint8_t *mbskip_table;\
\
    /**\
     * Motion vector table.\
     * @code\
     * example:\
     * int mv_sample_log2= 4 - motion_subsample_log2;\
     * int mb_width= (width+15)>>4;\
     * int mv_stride= (mb_width << mv_sample_log2) + 1;\
     * motion_val[direction][x + y*mv_stride][0->mv_x, 1->mv_y];\
     * @endcode\
     * - encoding: set by user\
     * - decoding: set by lavc\
     */\
    int16_t (*motion_val[2])[2];\
\
    /**\
     * Macroblock type table\
     * mb_type_base + mb_width + 2\
     * - encoding: set by user\
     * - decoding: set by lavc\
     */\
    uint32_t *mb_type;\
\
    /**\
     * log2 of the size of the block which a single vector in motion_val represents: \
     * (4->16x16, 3->8x8, 2-> 4x4, 1-> 2x2)\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    uint8_t motion_subsample_log2;\
\
    /**\
     * for some private data of the user\
     * - encoding: unused\
     * - decoding: set by user\
     */\
    void *opaque;\
\
    /**\
     * error\
     * - encoding: set by lavc if flags&CODEC_FLAG_PSNR\
     * - decoding: unused\
     */\
    uint64_t error[4];\
\
    /**\
     * type of the buffer (to keep track of who has to dealloc data[*])\
     * - encoding: set by the one who allocs it\
     * - decoding: set by the one who allocs it\
     * Note: user allocated (direct rendering) & internal buffers can not coexist currently\
     */\
    int type;\
    \
    /**\
     * when decoding, this signal how much the picture must be delayed.\
     * extra_delay = repeat_pict / (2*fps)\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    int repeat_pict;\
    \
    /**\
     * \
     */\
    int qscale_type;\
    \
    /**\
     * The content of the picture is interlaced.\
     * - encoding: set by user\
     * - decoding: set by lavc (default 0)\
     */\
    int interlaced_frame;\
    \
    /**\
     * if the content is interlaced, is top field displayed first.\
     * - encoding: set by user\
     * - decoding: set by lavc\
     */\
    int top_field_first;\
    \
    /**\
     * Pan scan.\
     * - encoding: set by user\
     * - decoding: set by lavc\
     */\
    AVPanScan *pan_scan;\
    \
    /**\
     * tell user application that palette has changed from previous frame.\
     * - encoding: ??? (no palette-enabled encoder yet)\
     * - decoding: set by lavc (default 0)\
     */\
    int palette_has_changed;\
    \
    /**\
     * Codec suggestion on buffer type if != 0\
     * - encoding: unused\
     * - decoding: set by lavc (before get_buffer() call))\
     */\
    int buffer_hints;\
\
    /**\
     * DCT coeffitients\
     * - encoding: unused\
     * - decoding: set by lavc\
     */\
    short *dct_coeff;\
\
    /**\
     * Motion referece frame index\
     * - encoding: set by user\
     * - decoding: set by lavc\
     */\
    int8_t *ref_index[2];

#define FF_QSCALE_TYPE_MPEG1 0
#define FF_QSCALE_TYPE_MPEG2 1
#define FF_QSCALE_TYPE_H264  2

#define FF_BUFFER_TYPE_INTERNAL 1
#define FF_BUFFER_TYPE_USER     2 ///< Direct rendering buffers (image is (de)allocated by user)
#define FF_BUFFER_TYPE_SHARED   4 ///< buffer from somewhere else, don't dealloc image (data/base), all other tables are not shared
#define FF_BUFFER_TYPE_COPY     8 ///< just a (modified) copy of some other buffer, don't dealloc anything


#define FF_I_TYPE 1 // Intra
#define FF_P_TYPE 2 // Predicted
#define FF_B_TYPE 3 // Bi-dir predicted
#define FF_S_TYPE 4 // S(GMC)-VOP MPEG4
#define FF_SI_TYPE 5
#define FF_SP_TYPE 6

#define FF_BUFFER_HINTS_VALID    0x01 // Buffer hints value is meaningful (if 0 ignore)
#define FF_BUFFER_HINTS_READABLE 0x02 // Codec will read from buffer
#define FF_BUFFER_HINTS_PRESERVE 0x04 // User must not alter buffer content
#define FF_BUFFER_HINTS_REUSABLE 0x08 // Codec will reuse the buffer (update)

/**
 * Audio Video Frame.
 */
typedef struct AVFrame {
    FF_COMMON_FRAME
} AVFrame;

#define DEFAULT_FRAME_RATE_BASE 1001000

/**
 * main external api structure.
 */
typedef struct AVCodecContext {
    /**
     * Info on struct for av_log
     * - set by avcodec_alloc_context
     */
    AVClass *av_class;
    /**
     * the average bitrate.
     * - encoding: set by user. unused for constant quantizer encoding
     * - decoding: set by lavc. 0 or some bitrate if this info is available in the stream
     */
    int bit_rate;

    /**
     * number of bits the bitstream is allowed to diverge from the reference.
     *           the reference can be CBR (for CBR pass1) or VBR (for pass2)
     * - encoding: set by user. unused for constant quantizer encoding
     * - decoding: unused
     */
    int bit_rate_tolerance;

    /**
     * CODEC_FLAG_*.
     * - encoding: set by user.
     * - decoding: set by user.
     */
    int flags;

    /**
     * some codecs needs additionnal format info. It is stored here
     * - encoding: set by user.
     * - decoding: set by lavc. (FIXME is this ok?)
     */
    int sub_id;

    /**
     * motion estimation algorithm used for video coding.
     * 1 (zero), 2 (full), 3 (log), 4 (phods), 5 (epzs), 6 (x1), 7 (hex),
     * 8 (umh), 9 (iter) [7, 8 are x264 specific, 9 is snow specific]
     * - encoding: MUST be set by user.
     * - decoding: unused
     */
    int me_method;

    /**
     * some codecs need / can use extra-data like huffman tables.
     * mjpeg: huffman tables
     * rv10: additional flags
     * mpeg4: global headers (they can be in the bitstream or here)
     * the allocated memory should be FF_INPUT_BUFFER_PADDING_SIZE bytes larger
     * then extradata_size to avoid prolems if its read with the bitstream reader
     * the bytewise contents of extradata must not depend on the architecture or cpu endianness
     * - encoding: set/allocated/freed by lavc.
     * - decoding: set/allocated/freed by user.
     */
    uint8_t *extradata;
    int extradata_size;

    /**
     * this is the fundamental unit of time (in seconds) in terms
     * of which frame timestamps are represented. for fixed-fps content,
     * timebase should be 1/framerate and timestamp increments should be
     * identically 1.
     * - encoding: MUST be set by user
     * - decoding: set by lavc.
     */
    AVRational time_base;

    /* video only */
    /**
     * picture width / height.
     * - encoding: MUST be set by user.
     * - decoding: set by lavc.
     * Note, for compatibility its possible to set this instead of
     * coded_width/height before decoding
     */
    int width, height;

#define FF_ASPECT_EXTENDED 15

    /**
     * the number of pictures in a group of pitures, or 0 for intra_only.
     * - encoding: set by user.
     * - decoding: unused
     */
    int gop_size;

    /**
     * pixel format, see PIX_FMT_xxx.
     * - encoding: set by user.
     * - decoding: set by lavc.
     */
    enum PixelFormat pix_fmt;

    /**
     * Frame rate emulation. If not zero lower layer (i.e. format handler)
     * has to read frames at native frame rate.
     * - encoding: set by user.
     * - decoding: unused.
     */
    int rate_emu;

    /**
     * if non NULL, 'draw_horiz_band' is called by the libavcodec
     * decoder to draw an horizontal band. It improve cache usage. Not
     * all codecs can do that. You must check the codec capabilities
     * before
     * - encoding: unused
     * - decoding: set by user.
     * @param height the height of the slice
     * @param y the y position of the slice
     * @param type 1->top field, 2->bottom field, 3->frame
     * @param offset offset into the AVFrame.data from which the slice should be read