typedefstruct AVIOContext{ const AVClass *av_class; unsignedchar *buffer; /**< Start of the buffer. */ int buffer_size; /**< Maximum buffer size */ unsignedchar *buf_ptr; /**< Current position in the buffer */ unsignedchar *buf_end; /**< End of the data */ int (*read_packet)(void *opaque, uint8_t *buf, int buf_size); int (*write_packet)(void *opaque, uint8_t *buf, int buf_size); int64_t (*seek)(void *opaque, int64_t offset, int whence); int64_t pos; /**< position in the file of the current buffer */ int must_flush; /**< true if the next seek should flush */ int eof_reached; /**< true if eof reached */ int write_flag; /**< true if open for writing */ int max_packet_size; unsignedlong checksum; unsignedchar *checksum_ptr; unsignedlong(*update_checksum)(unsignedlong checksum, const uint8_t *buf, unsignedint size); int error; /**< contains the error code or 0 if no error happened */ int (*read_pause)(void *opaque, int pause); int64_t (*read_seek)(void *opaque, int stream_index, int64_t timestamp, int flags); int seekable; int64_t maxsize; int direct; int64_t bytes_read; int seek_count; int writeout_count; int orig_buffer_size; int short_seek_threshold; }
typedefstruct URLProtocol { constchar *name; int (*url_open)(URLContext *h, constchar *url, int flags); int (*url_read)(URLContext *h, unsignedchar *buf, int size); int (*url_write)(URLContext *h, constunsignedchar *buf, int size); int64_t (*url_seek)(URLContext *h, int64_t pos, int whence); int (*url_close)(URLContext *h); struct URLProtocol *next; int (*url_read_pause)(URLContext *h, int pause); int64_t (*url_read_seek)(URLContext *h, int stream_index, int64_t timestamp, int flags); int (*url_get_file_handle)(URLContext *h); int priv_data_size; const AVClass *priv_data_class; int flags; int (*url_check)(URLContext *h, int mask); }
enum AVMediaType { AVMEDIA_TYPE_UNKNOWN = -1, ///< Usually treated as AVMEDIA_TYPE_DATA AVMEDIA_TYPE_VIDEO, AVMEDIA_TYPE_AUDIO, AVMEDIA_TYPE_DATA, ///< Opaque data information usually continuous AVMEDIA_TYPE_SUBTITLE, AVMEDIA_TYPE_ATTACHMENT, ///< Opaque data information usually sparse AVMEDIA_TYPE_NB };
sample_fmt(音频采样格式)
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enum AVSampleFormat { AV_SAMPLE_FMT_NONE = -1, AV_SAMPLE_FMT_U8, ///< unsigned 8 bits AV_SAMPLE_FMT_S16, ///< signed 16 bits AV_SAMPLE_FMT_S32, ///< signed 32 bits AV_SAMPLE_FMT_FLT, ///< float AV_SAMPLE_FMT_DBL, ///< double AV_SAMPLE_FMT_U8P, ///< unsigned 8 bits, planar AV_SAMPLE_FMT_S16P, ///< signed 16 bits, planar AV_SAMPLE_FMT_S32P, ///< signed 32 bits, planar AV_SAMPLE_FMT_FLTP, ///< float, planar AV_SAMPLE_FMT_DBLP, ///< double, planar AV_SAMPLE_FMT_NB ///< Number of sample formats. DO NOT USE if linking dynamically };
typedefstruct AVCodec{ constchar *name; constchar *long_name; enum AVMediaType type; enum AVCodecID id; int capabilities; const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0} constenum AVPixelFormat *pix_fmts; ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1 constint *supported_samplerates; ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0 constenum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1 constuint64_t *channel_layouts; ///< array of support channel layouts, or NULL if unknown. array is terminated by 0 uint8_t max_lowres; ///< maximum value for lowres supported by the decoder, no direct access, use av_codec_get_max_lowres() const AVClass *priv_class; ///< AVClass for the private context const AVProfile *profiles; ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN} int priv_data_size; struct AVCodec *next; int (*init_thread_copy)(AVCodecContext *); int (*update_thread_context)(AVCodecContext *dst, const AVCodecContext *src); const AVCodecDefault *defaults; void (*init_static_data)(struct AVCodec *codec);
int (*init)(AVCodecContext *); int (*encode_sub)(AVCodecContext *, uint8_t *buf, int buf_size, int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr); int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt); int (*close)(AVCodecContext *); void (*flush)(AVCodecContext *); int caps_internal; }
name : 具体的 CODEC 的名称的简短描述，比如 “HEVC”/“H264” 等
long_name : CODEC 名称的详细描述，比如 “HEVC (High Efficiency Video Coding)”
type : 媒体类型的字段，它是 enum 型的，表示视频、音频、字幕等，比如AVMEDIA_TYPE_VIDEO、AVMEIDA_TYPE_AUDIO
enum AVMediaType { AVMEDIA_TYPE_UNKNOWN = -1, ///< Usually treated as AVMEDIA_TYPE_DATA AVMEDIA_TYPE_VIDEO, AVMEDIA_TYPE_AUDIO, AVMEDIA_TYPE_DATA, ///< Opaque data information usually continuous AVMEDIA_TYPE_SUBTITLE, AVMEDIA_TYPE_ATTACHMENT, ///< Opaque data information usually sparse AVMEDIA_TYPE_NB }
enum AVPixelFormat { AV_PIX_FMT_NONE = -1, AV_PIX_FMT_YUV420P, ///< planar YUV 4:2:0, 12bpp, (1 Cr & Cb sample per 2x2 Y samples) AV_PIX_FMT_YUYV422, ///< packed YUV 4:2:2, 16bpp, Y0 Cb Y1 Cr AV_PIX_FMT_RGB24, ///< packed RGB 8:8:8, 24bpp, RGBRGB... AV_PIX_FMT_BGR24, ///< packed RGB 8:8:8, 24bpp, BGRBGR... AV_PIX_FMT_YUV422P, ///< planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples) AV_PIX_FMT_YUV444P, ///< planar YUV 4:4:4, 24bpp, (1 Cr & Cb sample per 1x1 Y samples) AV_PIX_FMT_YUV410P, ///< planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples) AV_PIX_FMT_YUV411P, ///< planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples) AV_PIX_FMT_GRAY8, ///< Y , 8bpp AV_PIX_FMT_MONOWHITE, ///< Y , 1bpp, 0 is white, 1 is black, in each byte pixels are ordered from the msb to the lsb AV_PIX_FMT_MONOBLACK, ///< Y , 1bpp, 0 is black, 1 is white, in each byte pixels are ordered from the msb to the lsb AV_PIX_FMT_PAL8, ///< 8 bit with PIX_FMT_RGB32 palette AV_PIX_FMT_YUVJ420P, ///< planar YUV 4:2:0, 12bpp, full scale (JPEG), deprecated in favor of PIX_FMT_YUV420P and setting color_range AV_PIX_FMT_YUVJ422P, ///< planar YUV 4:2:2, 16bpp, full scale (JPEG), deprecated in favor of PIX_FMT_YUV422P and setting color_range AV_PIX_FMT_YUVJ444P, ///< planar YUV 4:4:4, 24bpp, full scale (JPEG), deprecated in favor of PIX_FMT_YUV444P and setting color_range AV_PIX_FMT_XVMC_MPEG2_MC,///< XVideo Motion Acceleration via common packet passing AV_PIX_FMT_XVMC_MPEG2_IDCT, ... }
const enum AVSampleFormat *sample_fmts
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enum AVSampleFormat { AV_SAMPLE_FMT_NONE = -1, AV_SAMPLE_FMT_U8, ///< unsigned 8 bits AV_SAMPLE_FMT_S16, ///< signed 16 bits AV_SAMPLE_FMT_S32, ///< signed 32 bits AV_SAMPLE_FMT_FLT, ///< float AV_SAMPLE_FMT_DBL, ///< double AV_SAMPLE_FMT_U8P, ///< unsigned 8 bits, planar AV_SAMPLE_FMT_S16P, ///< signed 16 bits, planar AV_SAMPLE_FMT_S32P, ///< signed 32 bits, planar AV_SAMPLE_FMT_FLTP, ///< float, planar AV_SAMPLE_FMT_DBLP, ///< double, planar AV_SAMPLE_FMT_NB ///< Number of sample formats. DO NOT USE if linking dynamically };
typedefstruct AVFrame{ uint8_t *data[AV_NUM_DATA_POINTERS]; int linesize[AV_NUM_DATA_POINTERS]; uint8_t **extended_data; int width, height; int nb_samples; /* number of audio samples(per channel) described by this frame */ int format; int key_frame; /* 1->keyframe, 0->not*/ enum AVPictureType pict_type; AVRational sample_aspect_ratio; int64_t pts; int64_t pkt_pts; int64_t pkt_dts; int coded_picture_number; int display_picture_number; int quality; void *opaque; /* for some private data of the user */ uint64_t error[AV_NUM_DATA_POINTERS]; int repeat_pict; int interlaced_frame; int top_field_first; /* If the content is interlaced, is top field displayed first */ int palette_has_changed; int64_t reordered_opaque; int sample_rate; /*Sample rate of the audio data*/ uint64_t channel_layout; /*channel layout of the audio data*/ AVBufferRef *buf[AV_NUM_DATA_POINTERS]; AVBufferRef **extended_buf; int nb_exteneded_buf; AVFrameSideData **side_data; int nb_side_data;
