企业网网站怎么做,可以做长图的网站,seo外包优化,广州免费领养猫咪参考链接
FFmpeg源代码结构图 - 解码_雷霄骅的博客-CSDN博客_ffmpeg雷霄骅函数背景色
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…参考链接
FFmpeg源代码结构图 - 解码_雷霄骅的博客-CSDN博客_ffmpeg雷霄骅函数背景色
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处理协议Protocol的功能。绿色背景的函数AVInputFormat结构体中的函数包含处理封装格式Format的功能。蓝色背景的函数AVCodec结构体中的函数包含了编解码器Codec的功能。PSURLProtocolAVInputFormatAVCodec在FFmpeg开始运行并且注册完组件之后都会分别被连接成一个个的链表。因此实际上是有很多的URLProtocolAVInputFormatAVCodec的。图中画出了解码一个输入协议是“文件”其实就是打开一个文件。“文件”也被当做是一种广义的协议封装格式为FLV视频编码格式是H.264的数据的函数调用关系。
区域
整个架构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通用架构通用流程右上方黄色区域——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MKVFLVMPEGTSAVI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黑色箭头线标志了函数之间的调用关系。红色的箭头线标志了解码的流程。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AVInputFormat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
每个函数旁边标识了它所在的文件的路径。此外还有一点需要注意的是一些API函数内部也调用了另一些API函数。也就是说API函数并不一定全部都调用FFmpeg的内部函数他也有可能调用其他的API函数。 例如从图中可以看出来avformat_close_input()调用了avformat_free_context()和avio_close()。这些在内部代码中被调用的API函数也标记为粉红色。
现在的执行流程
FFmpeg在avcodec.register_all被弃用后新的流程_弥彦已死的博客-CSDN博客从学龄前开始解读FFMPEG代码 之 avcodec_register_all函数_zzyincsdn的博客-CSDN博客模块介绍
右上区域URLProtocol协议处理函数
URLProtocol结构体包含如下协议处理函数指针 url_open()打开url_read()读取url_write()写入url_seek()调整进度url_close()关闭结构体代码
typedef struct URLProtocol {const char *name;int (*url_open)( URLContext *h, const char *url, int flags);/*** This callback is to be used by protocols which open further nested* protocols. options are then to be passed to ffurl_open_whitelist()* or ffurl_connect() for those nested protocols.*/int (*url_open2)(URLContext *h, const char *url, int flags, AVDictionary **options);int (*url_accept)(URLContext *s, URLContext **c);int (*url_handshake)(URLContext *c);/*** Read data from the protocol.* If data is immediately available (even less than size), EOF is* reached or an error occurs (including EINTR), return immediately.* Otherwise:* In non-blocking mode, return AVERROR(EAGAIN) immediately.* In blocking mode, wait for data/EOF/error with a short timeout (0.1s),* and return AVERROR(EAGAIN) on timeout.* Checking interrupt_callback, looping on EINTR and EAGAIN and until* enough data has been read is left to the calling function; see* retry_transfer_wrapper in avio.c.*/int (*url_read)( URLContext *h, unsigned char *buf, int size);int (*url_write)(URLContext *h, const unsigned char *buf, int size);int64_t (*url_seek)( URLContext *h, int64_t pos, int whence);int (*url_close)(URLContext *h);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 (*url_get_multi_file_handle)(URLContext *h, int **handles,int *numhandles);int (*url_get_short_seek)(URLContext *h);int (*url_shutdown)(URLContext *h, int flags);const AVClass *priv_data_class;int priv_data_size;int flags;int (*url_check)(URLContext *h, int mask);int (*url_open_dir)(URLContext *h);int (*url_read_dir)(URLContext *h, AVIODirEntry **next);int (*url_close_dir)(URLContext *h);int (*url_delete)(URLContext *h);int (*url_move)(URLContext *h_src, URLContext *h_dst);const char *default_whitelist;
} URLProtocol; 注意事项
【例子】不同的协议对应着上述接口有不同的实现函数举几个例子File协议即文件对应的URLProtocol结构体ff_file_protocolff_file_protocol结构体的文件在libavformat/file.c url_open() - file_open() - open()url_read() - file_read() - read()url_write() - file_write() - write()url_seek() - file_seek() - lseek()url_close() - file_close() - close()
const URLProtocol ff_file_protocol {.name file,.url_open file_open,.url_read file_read,.url_write file_write,.url_seek file_seek,.url_close file_close,.url_get_file_handle file_get_handle,.url_check file_check,.url_delete file_delete,.url_move file_move,.priv_data_size sizeof(FileContext),.priv_data_class file_class,.url_open_dir file_open_dir,.url_read_dir file_read_dir,.url_close_dir file_close_dir,.default_whitelist file,crypto,data
};
RTMP协议libRTMP对应的URLProtocol结构体ff_librtmp_protocolff_librtmp_protocol结构体的文件在libavformat/protocol url_open() - rtmp_open() - RTMP_Init(), RTMP_SetupURL(), RTMP_Connect(), RTMP_ConnectStream()url_read() - rtmp_read() - RTMP_Read()url_write() - rtmp_write() - RTMP_Write()url_seek() - rtmp_read_seek() - RTMP_SendSeek()url_close() - rtmp_close() - RTMP_Close()
RTMP_CLASS(rtmp)
const URLProtocol ff_librtmp_protocol {.name rtmp,.url_open rtmp_open,.url_read rtmp_read,.url_write rtmp_write,.url_close rtmp_close,.url_read_pause rtmp_read_pause,.url_read_seek rtmp_read_seek,.url_get_file_handle rtmp_get_file_handle,.priv_data_size sizeof(LibRTMPContext),.priv_data_class librtmp_class,.flags URL_PROTOCOL_FLAG_NETWORK,
};
UDP协议对应的URLProtocol结构体ff_udp_protocolff_udp_protocol结构体位于libavformat/udp.c url_open() - udp_open()url_read() - udp_read()url_write() - udp_write()url_seek() - udp_close()url_close() - udp_close()
const URLProtocol ff_udp_protocol {.name udp,.url_open udp_open,.url_read udp_read,.url_write udp_write,.url_close udp_close,.url_get_file_handle udp_get_file_handle,.priv_data_size sizeof(UDPContext),.priv_data_class udp_class,.flags URL_PROTOCOL_FLAG_NETWORK,
};
右中区域AVInputFormat封装格式处理函数
AVInputFormat包含如下封装格式处理函数指针 read_probe()检查格式read_header()读取文件头read_packet()读取一帧数据read_seek()调整进度read_close()关闭注意事项
【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AVInputFormat结构体ff_flv_demuxer read_probe() - flv_probe() – probe()read_header() - flv_read_header() - create_stream() - avformat_new_stream()read_packet() - flv_read_packet()read_seek() - flv_read_seek()read_close() - flv_read_close()FFmpeg: libavformat/flvdec.c File Reference{.name flv,.long_name NULL_IF_CONFIG_SMALL(FLV (Flash Video)),.priv_data_size sizeof(FLVContext),.read_probe flv_probe,.read_header flv_read_header,.read_packet flv_read_packet,.read_seek flv_read_seek,.read_close flv_read_close,.extensions flv,.priv_class flv_class,
}
MKV封装格式对应的AVInputFormat结构体ff_matroska_demuxer read_probe() - matroska_probe()read_header() - matroska_read_header()read_packet() - matroska_read_packet()read_seek() - matroska_read_seek()read_close() - matroska_read_close()参考链接FFmpeg: libavformat/matroskadec.c File Reference{.name matroska,webm,.long_name NULL_IF_CONFIG_SMALL(Matroska / WebM),.extensions mkv,mk3d,mka,mks,.priv_data_size sizeof(MatroskaDemuxContext),.read_probe matroska_probe,.read_header matroska_read_header,.read_packet matroska_read_packet,.read_close matroska_read_close,.read_seek matroska_read_seek,.mime_type audio/webm,audio/x-matroska,video/webm,video/x-matroska
}
MPEG2TS封装格式对应的AVInputFormat结构体ff_mpegts_demuxer read_probe() - mpegts_probe()read_header() - mpegts_read_header()read_packet() - mpegts_read_packet() read_close() - mpegts_read_close()参考链接FFmpeg: libavformat/mpegts.c File Reference{.name mpegts,.long_name NULL_IF_CONFIG_SMALL(MPEG-TS (MPEG-2 Transport Stream)),.priv_data_size sizeof(MpegTSContext),.read_probe mpegts_probe,.read_header mpegts_read_header,.read_packet mpegts_read_packet,.read_close mpegts_read_close,.read_timestamp mpegts_get_dts,.flags AVFMT_SHOW_IDS | AVFMT_TS_DISCONT,.priv_class mpegts_class,
}
AVI封装格式对应的AVInputFormat结构体ff_avi_demuxer read_probe() - avi_probe()read_header() - avi_read_header()read_packet() - avi_read_packet()read_seek() - avi_read_seek()read_close() - avi_read_close()参考链接FFmpeg: libavformat/avidec.c File Reference{.name avi,.long_name NULL_IF_CONFIG_SMALL(AVI (Audio Video Interleaved)),.priv_data_size sizeof(AVIContext),.extensions avi,.read_probe avi_probe,.read_header avi_read_header,.read_packet avi_read_packet,.read_close avi_read_close,.read_seek avi_read_seek,.priv_class demuxer_class,
}
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decode()解码一帧数据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解码对应的AVCodec结构体ff_hevc_decoder init() - hevc_decode_init()decode() - hevc_decode_frame() - decode_nal_units()close() - hevc_decode_free()参考链接FFmpeg: libavcodec/hevc.c File Reference{.name hevc,.long_name NULL_IF_CONFIG_SMALL(HEVC (High Efficiency Video Coding)),.type AVMEDIA_TYPE_VIDEO,.id AV_CODEC_ID_HEVC,.priv_data_size sizeof(HEVCContext),.priv_class hevc_decoder_class,.init hevc_decode_init,.close hevc_decode_free,.decode ,.flush hevc_decode_flush,.update_thread_context hevc_update_thread_context,.init_thread_copy hevc_init_thread_copy,.capabilities AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |AV_CODEC_CAP_SLICE_THREADS | AV_CODEC_CAP_FRAME_THREADS,.profiles NULL_IF_CONFIG_SMALL(profiles),
}
H.264解码对应的AVCodec结构体ff_h264_decoder init() - ff_h264_decode_init()decode() - h264_decode_frame() - decode_nal_units()close() - h264_decode_end()参考链接FFmpeg: libavcodec/h264.c File Reference{.name h264,.long_name NULL_IF_CONFIG_SMALL(H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10),.type AVMEDIA_TYPE_VIDEO,.id AV_CODEC_ID_H264,.priv_data_size sizeof(H264Context),.init ff_h264_decode_init,.close h264_decode_end,.decode h264_decode_frame,.capabilities AV_CODEC_CAP_DR1 |AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS |AV_CODEC_CAP_FRAME_THREADS,.flush flush_dpb,.init_thread_copy ONLY_IF_THREADS_ENABLED(decode_init_thread_copy),.update_thread_context ONLY_IF_THREADS_ENABLED(ff_h264_update_thread_context),.profiles NULL_IF_CONFIG_SMALL(profiles),.priv_class h264_class,
}
VP8解码libVPX对应的AVCodec结构体ff_libvpx_vp8_decoder init() - vpx_init() - vpx_codec_dec_init()decode() - vp8_decode() - vpx_codec_decode(), vpx_codec_get_frame()close() - vp8_free() - vpx_codec_destroy()版本差异参考链接FFmpeg: libavcodec/libvpxdec.c Source File
AVCodec ff_libvpx_vp8_decoder {.name libvpx,.type AVMEDIA_TYPE_VIDEO,.id AV_CODEC_ID_VP8,.priv_data_size sizeof(VP8Context),.init vp8_init,.close vp8_free,.decode vp8_decode,.capabilities CODEC_CAP_AUTO_THREADS | CODEC_CAP_DR1,.long_name NULL_IF_CONFIG_SMALL(libvpx VP8),
};
MPEG2解码对应的AVCodec结构体ff_mpeg2video_decoder init() - mpeg_decode_init()decode() - mpeg_decode_frame()close() - mpeg_decode_end()参考链接FFmpeg: libavcodec/mpeg12dec.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(Mpeg1Context),.init mpeg_decode_init,.close mpeg_decode_end,.decode mpeg_decode_frame,.capabilities AV_CODEC_CAP_DRAW_HORIZ_BAND | AV_CODEC_CAP_DR1 |AV_CODEC_CAP_TRUNCATED | AV_CODEC_CAP_DELAY |AV_CODEC_CAP_SLICE_THREADS,.flush flush,.max_lowres 3,.profiles NULL_IF_CONFIG_SMALL(mpeg2_video_profiles),
} 注意事项
FFmpeg (libav*) 开发踩过的坑 - 哔哩哔哩
