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FFmpeg源代码结构图 - 编码_雷霄骅的博客-CSDN博客_ffmpeg 源码函数背景色
函数在图中以方框的形式表现出来。不同的背景色标志了该函数不同的作用#xff1a; 粉红色背景函数#xff1a;FFmpeg的API函数。白色背景的函数#xff1a;FFmpeg的内部函数。黄色背景的…参考链接
FFmpeg源代码结构图 - 编码_雷霄骅的博客-CSDN博客_ffmpeg 源码函数背景色
函数在图中以方框的形式表现出来。不同的背景色标志了该函数不同的作用 粉红色背景函数FFmpeg的API函数。白色背景的函数FFmpeg的内部函数。黄色背景的函数URLProtocol结构体中的函数包含了读写各种协议的功能。绿色背景的函数AVOutputFormat结构体中的函数包含了读写各种封装格式的功能。蓝色背景的函数AVCodec结构体中的函数包含了编解码的功能。
区域
整个关系图可以分为以下几个区域 左边区域——架构函数区域这些函数并不针对某一特定的视频格式。右上方黄色区域——协议处理函数区域不同的协议RTPRTMPFILE会调用不同的协议处理函数。右边中间绿色区域——封装格式处理函数区域不同的封装格式MKVFLVMPEG2TSAVI会调用不同的封装格式处理函数。右边下方蓝色区域——编解码函数区域不同的编码标准HEVCH.264MPEG2会调用不同的编解码函数。
箭头线
为了把调用关系表示的更明显图中的箭头线也使用了不同的颜色 红色的箭头线标志了编码的流程。其他颜色的箭头线标志了函数之间的调用关系。其中 调用URLProtocol结构体中的函数用黄色箭头线标识调用AVOutputFormat结构体中的函数用绿色箭头线标识调用AVCodec结构体中的函数用蓝色箭头线标识。
函数所在的文件
每个函数标识了它所在的文件路径。
模块介绍
和解码重合的内容请参考下面的链接FFmpeg源代码简单分析-架构图-解码_MY CUP OF TEA的博客-CSDN博客
右中区域AVOutputFormat封装格式处理函数
AVOutputFormat包含如下封装格式处理函数指针 write_header()写文件头write_packet()写一帧数据write_trailer()写文件尾参考链接FFmpeg: AVOutputFormat Struct Reference
typedef struct AVOutputFormat {const char *name;/*** Descriptive name for the format, meant to be more human-readable* than name. You should use the NULL_IF_CONFIG_SMALL() macro* to define it.*/const char *long_name;const char *mime_type;const char *extensions; /** comma-separated filename extensions *//* output support */enum AVCodecID audio_codec; /** default audio codec */enum AVCodecID video_codec; /** default video codec */enum AVCodecID subtitle_codec; /** default subtitle codec *//*** can use flags: AVFMT_NOFILE, AVFMT_NEEDNUMBER,* AVFMT_GLOBALHEADER, AVFMT_NOTIMESTAMPS, AVFMT_VARIABLE_FPS,* AVFMT_NODIMENSIONS, AVFMT_NOSTREAMS, AVFMT_ALLOW_FLUSH,* AVFMT_TS_NONSTRICT, AVFMT_TS_NEGATIVE*/int flags;/*** List of supported codec_id-codec_tag pairs, ordered by better* choice first. The arrays are all terminated by AV_CODEC_ID_NONE.*/const struct AVCodecTag * const *codec_tag;const AVClass *priv_class; /// AVClass for the private context/****************************************************************** No fields below this line are part of the public API. They* may not be used outside of libavformat and can be changed and* removed at will.* New public fields should be added right above.******************************************************************//*** size of private data so that it can be allocated in the wrapper*/int priv_data_size;/*** Internal flags. See FF_FMT_FLAG_* in internal.h.*/int flags_internal;int (*write_header)(struct AVFormatContext *);/*** Write a packet. If AVFMT_ALLOW_FLUSH is set in flags,* pkt can be NULL in order to flush data buffered in the muxer.* When flushing, return 0 if there still is more data to flush,* or 1 if everything was flushed and there is no more buffered* data.*/int (*write_packet)(struct AVFormatContext *, AVPacket *pkt);int (*write_trailer)(struct AVFormatContext *);/*** A format-specific function for interleavement.* If unset, packets will be interleaved by dts.** param s An AVFormatContext for output. pkt will be added to* resp. taken from its packet buffer.* param[in,out] pkt A packet to be interleaved if has_packet is set;* also used to return packets. If no packet is returned* (e.g. on error), pkt is blank on return.* param flush 1 if no further packets are available as input and* all remaining packets should be output.* param has_packet If set, pkt contains a packet to be interleaved* on input; otherwise pkt is blank on input.* return 1 if a packet was output, 0 if no packet could be output,* 0 if an error occurred*/int (*interleave_packet)(struct AVFormatContext *s, AVPacket *pkt,int flush, int has_packet);/*** Test if the given codec can be stored in this container.** return 1 if the codec is supported, 0 if it is not.* A negative number if unknown.* MKTAG(A, P, I, C) if the codec is only supported as AV_DISPOSITION_ATTACHED_PIC*/int (*query_codec)(enum AVCodecID id, int std_compliance);void (*get_output_timestamp)(struct AVFormatContext *s, int stream,int64_t *dts, int64_t *wall);/*** Allows sending messages from application to device.*/int (*control_message)(struct AVFormatContext *s, int type,void *data, size_t data_size);/*** Write an uncoded AVFrame.** See av_write_uncoded_frame() for details.** The library will free *frame afterwards, but the muxer can prevent it* by setting the pointer to NULL.*/int (*write_uncoded_frame)(struct AVFormatContext *, int stream_index,AVFrame **frame, unsigned flags);/*** Returns device list with it properties.* see avdevice_list_devices() for more details.*/int (*get_device_list)(struct AVFormatContext *s, struct AVDeviceInfoList *device_list);enum AVCodecID data_codec; /** default data codec *//*** Initialize format. May allocate data here, and set any AVFormatContext or* AVStream parameters that need to be set before packets are sent.* This method must not write output.** Return 0 if streams were fully configured, 1 if not, negative AVERROR on failure** Any allocations made here must be freed in deinit().*/int (*init)(struct AVFormatContext *);/*** Deinitialize format. If present, this is called whenever the muxer is being* destroyed, regardless of whether or not the header has been written.** If a trailer is being written, this is called after write_trailer().** This is called if init() fails as well.*/void (*deinit)(struct AVFormatContext *);/*** Set up any necessary bitstream filtering and extract any extra data needed* for the global header.** note pkt might have been directly forwarded by a meta-muxer; therefore* pkt-stream_index as well as the pkts timebase might be invalid.* Return 0 if more packets from this stream must be checked; 1 if not.*/int (*check_bitstream)(struct AVFormatContext *s, struct AVStream *st,const AVPacket *pkt);
} AVOutputFormat;
注意事项
【例子】不同的封装格式对应着上述接口有不同的实现函数举几个例子FLV封装格式对应的AVOutputFormat结构体ff_flv_muxer write_header() - flv_write_header()write_packet() – flv_write_packet()write_trailer() - flv_write_trailer()参考链接FFmpeg: libavformat/flvenc.c File Reference{.name flv,.long_name NULL_IF_CONFIG_SMALL(FLV (Flash Video)),.mime_type video/x-flv,.extensions flv,.priv_data_size sizeof(FLVContext),.audio_codec CONFIG_LIBMP3LAME ? AV_CODEC_ID_MP3 : AV_CODEC_ID_ADPCM_SWF,.video_codec AV_CODEC_ID_FLV1,.write_header flv_write_header,.write_packet flv_write_packet,.write_trailer flv_write_trailer,.codec_tag (const * const []) {flv_video_codec_ids, flv_audio_codec_ids, 0},.flags AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |AVFMT_TS_NONSTRICT,
}
MKV封装格式对应的AVOutputFormat结构体ff_matroska_muxer write_header() - mkv_write_header()write_packet() – mkv_write_flush_packet()write_trailer() - mkv_write_trailer()结构体ff_matroska_muxer 已经不存在参考链接FFmpeg: libavformat/matroskaenc.c Source Fileconst AVOutputFormat ff_matroska_muxer {.name matroska,.long_name NULL_IF_CONFIG_SMALL(Matroska),.mime_type video/x-matroska,.extensions mkv,.priv_data_size sizeof(MatroskaMuxContext),.audio_codec CONFIG_LIBVORBIS_ENCODER ?AV_CODEC_ID_VORBIS : AV_CODEC_ID_AC3,.video_codec CONFIG_LIBX264_ENCODER ?AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4,.init mkv_init,.deinit mkv_deinit,.write_header mkv_write_header,.write_packet mkv_write_flush_packet,.write_trailer mkv_write_trailer,.flags AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |AVFMT_TS_NONSTRICT | AVFMT_ALLOW_FLUSH,.codec_tag (const AVCodecTag* const []){ff_codec_bmp_tags, ff_codec_wav_tags,additional_audio_tags, additional_video_tags, additional_subtitle_tags, 0},.subtitle_codec AV_CODEC_ID_ASS,.query_codec mkv_query_codec,.check_bitstream mkv_check_bitstream,.priv_class matroska_webm_class,};#endif
MPEG2TS封装格式对应的AVOutputFormat结构体ff_mpegts_muxer write_header() - mpegts_write_header()write_packet() – mpegts_write_packet()write_trailer() - mpegts_write_end()参考链接FFmpeg: libavformat/mpegtsenc.c File Reference{.name mpegts,.long_name NULL_IF_CONFIG_SMALL(MPEG-TS (MPEG-2 Transport Stream)),.mime_type video/MP2T,.extensions ts,m2t,m2ts,mts,.priv_data_size sizeof(MpegTSWrite),.audio_codec AV_CODEC_ID_MP2,.video_codec AV_CODEC_ID_MPEG2VIDEO,.write_header mpegts_write_header,.write_packet mpegts_write_packet,.write_trailer mpegts_write_end,.flags AVFMT_ALLOW_FLUSH | AVFMT_VARIABLE_FPS,.priv_class mpegts_muxer_class,
}
AVI封装格式对应的AVOutputFormat结构体ff_avi_muxer write_header() - avi_write_header()write_packet() – avi_write_packet()write_trailer() - avi_write_trailer()参考链接FFmpeg: libavformat/avienc.c File Reference{.name avi,.long_name NULL_IF_CONFIG_SMALL(AVI (Audio Video Interleaved)),.mime_type video/x-msvideo,.extensions avi,.priv_data_size sizeof(AVIContext),.audio_codec CONFIG_LIBMP3LAME ? AV_CODEC_ID_MP3 : AV_CODEC_ID_AC3,.video_codec AV_CODEC_ID_MPEG4,.write_header avi_write_header,.write_packet avi_write_packet,.write_trailer avi_write_trailer,.codec_tag (const AVCodecTag * const []) {ff_codec_bmp_tags, ff_codec_wav_tags, 0},
}
右下区域AVCodec编解码函数
AVCodec包含如下编解码函数指针 init()初始化encode2()编码一帧数据close()关闭参考链接FFmpeg: AVCodec Struct Reference上述参考链接里面包含的结构体包含上述编解码函数指针但是新版本好像没有了
typedef struct AVCodec {/*** Name of the codec implementation.* The name is globally unique among encoders and among decoders (but an* encoder and a decoder can share the same name).* This is the primary way to find a codec from the user perspective.*/const char *name;/*** Descriptive name for the codec, meant to be more human readable than name.* You should use the NULL_IF_CONFIG_SMALL() macro to define it.*/const char *long_name;enum AVMediaType type;enum AVCodecID id;/*** Codec capabilities.* see AV_CODEC_CAP_**/int capabilities;uint8_t max_lowres; /// maximum value for lowres supported by the decoderconst AVRational *supported_framerates; /// array of supported framerates, or NULL if any, array is terminated by {0,0}const enum AVPixelFormat *pix_fmts; /// array of supported pixel formats, or NULL if unknown, array is terminated by -1const int *supported_samplerates; /// array of supported audio samplerates, or NULL if unknown, array is terminated by 0const enum AVSampleFormat *sample_fmts; /// array of supported sample formats, or NULL if unknown, array is terminated by -1
#if FF_API_OLD_CHANNEL_LAYOUT/*** deprecated use ch_layouts instead*/attribute_deprecatedconst uint64_t *channel_layouts; /// array of support channel layouts, or NULL if unknown. array is terminated by 0
#endifconst AVClass *priv_class; /// AVClass for the private contextconst AVProfile *profiles; /// array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}/*** Group name of the codec implementation.* This is a short symbolic name of the wrapper backing this codec. A* wrapper uses some kind of external implementation for the codec, such* as an external library, or a codec implementation provided by the OS or* the hardware.* If this field is NULL, this is a builtin, libavcodec native codec.* If non-NULL, this will be the suffix in AVCodec.name in most cases* (usually AVCodec.name will be of the form codec_name_wrapper_name).*/const char *wrapper_name;/*** Array of supported channel layouts, terminated with a zeroed layout.*/const AVChannelLayout *ch_layouts;
} AVCodec;
注意事项
【例子】不同的编解码器对应着上述接口有不同的实现函数举几个例子HEVC编码器对应的AVCodec结构体ff_libx265_encoder init() - libx265_encode_init() - x265_param_alloc(), x265_param_default_preset(), x265_encoder_open()encode2() - libx265_encode_frame() - x265_encoder_encode()close() - libx265_encode_close() - x265_param_free(), x265_encoder_close()参考链接FFmpeg: libavcodec/libx265.c File Reference{.name libx265,.long_name NULL_IF_CONFIG_SMALL(libx265 H.265 / HEVC),.type AVMEDIA_TYPE_VIDEO,.id AV_CODEC_ID_HEVC,.init libx265_encode_init,.init_static_data libx265_encode_init_csp,.encode2 libx265_encode_frame,.close libx265_encode_close,.priv_data_size sizeof(libx265Context),.priv_class class,.defaults x265_defaults,.capabilities AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AUTO_THREADS,
}
H.264编码器对应的AVCodec结构体ff_libx264_encoder init() - X264_init() - x264_param_default(), x264_encoder_open(), x264_encoder_headers()encode2() - X264_frame() - x264_encoder_encode()close() - X264_close() - x264_encoder_close()参考链接FFmpeg: libavcodec/libx264.c File Reference
{.name libx264,.type AVMEDIA_TYPE_VIDEO,.id CODEC_ID_H264,.priv_data_size sizeof(X264Context),.init X264_init,.encode X264_frame,.close X264_close,.capabilities CODEC_CAP_DELAY,.pix_fmts (const enum PixelFormat[]) { PIX_FMT_YUV420P, PIX_FMT_YUVJ420P, PIX_FMT_NONE },.long_name NULL_IF_CONFIG_SMALL(libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10),.priv_class class,
}
VP8编码器libVPX对应的AVCodec结构体ff_libvpx_vp8_encoder init() - vpx_init() - vpx_codec_enc_config_default()encode2() - vp8_encode() - vpx_codec_enc_init(), vpx_codec_encode()close() - vp8_free() - vpx_codec_destroy()参考链接FFmpeg/libvpxenc.c at master · FFmpeg/FFmpeg · GitHub
const FFCodec ff_libvpx_vp8_encoder {.p.name libvpx,.p.long_name NULL_IF_CONFIG_SMALL(libvpx VP8),.p.type AVMEDIA_TYPE_VIDEO,.p.id AV_CODEC_ID_VP8,.p.capabilities AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |AV_CODEC_CAP_OTHER_THREADS,.priv_data_size sizeof(VPxContext),.init vp8_init,FF_CODEC_ENCODE_CB(vpx_encode),.close vpx_free,.caps_internal FF_CODEC_CAP_AUTO_THREADS,.p.pix_fmts (const enum AVPixelFormat[]){ AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_NONE },.p.priv_class class_vp8,.defaults defaults,.p.wrapper_name libvpx,
};
MPEG2编码器对应的AVCodec结构体ff_mpeg2video_encoder init() - encode_init()encode2() - ff_mpv_encode_picture()close() - ff_mpv_encode_end()参考链接FFmpeg: libavcodec/mpeg12enc.c File Reference{.name mpeg2video,.long_name NULL_IF_CONFIG_SMALL(MPEG-2 video),.type AVMEDIA_TYPE_VIDEO,.id AV_CODEC_ID_MPEG2VIDEO,.priv_data_size sizeof(MpegEncContext),.init encode_init,.encode2 ff_mpv_encode_picture,.close ff_mpv_encode_end,.supported_framerates ff_mpeg2_frame_rate_tab,.pix_fmts (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,AV_PIX_FMT_YUV422P,AV_PIX_FMT_NONE },.capabilities AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS,.priv_class mpeg2_class,
}
