[ffmpeg] 录制

整理 ffmpeg 录制用到的一些 API，以及一些明白
API调用

常用API

1. AVFormatContext *avformat_alloc_context(void); // 创建 avformat 上下文结构体
2. void avformat_free_context(AVFormatContext *s);//
3. int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename); // 创建 avformat 上下文结构体，并设置输出格式，这边的 filename 主要用来推测 oformat 的格式，并设置 url 参数
4. AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c); // 向 format 上下文，插入新的 stream，索引号为之前的 stream 个数
5. int avformat_write_header(AVFormatContext *s, AVDictionary **options); // 写头信息 s->oformat->write_header，具体函数到 muxer_list 查找
6. int av_write_frame(AVFormatContext *s, AVPacket *pkt); // 写数据 s->oformat->write_packet, 需要外部释放，应该是因为这个接口调用之后 Pkt 数据就同步写入了，所以可以外部控制释放
7. int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt); // 交织写入数据，内部释放 pkt，这个接口把 pkt 传入不一定马上写入，可能会缓存到堆栈中，等交织之后才写入，所以外部控制不了什么时候释放
8. int av_write_trailer(AVFormatContext *s); // 把缓存的交织数据都写入文件，并写文件尾 s->oformat->write_trailer
9. void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output); // 打印输入和输出的详细格式信息
10. void avformat_close_input(AVFormatContext **s); // 释放 avformat 上下文结构体 和 调用 avio_close 关闭 AVIO
11. int avio_open(AVIOContext **s, const char *url, int flags); // 创建并初始化 AVIO 上下文
12. int avio_closep(AVIOContext **s); // 关闭 AVIO 上下文，并设置指针为 NULL
13. int avcodec_parameters_from_context(AVCodecParameters *par, const AVCodecContext *codec); // 将 codec 的参数拷贝到 par

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class

1. static const AVClass av_format_context_class = {
2.         .class_name     = "AVFormatContext",
3.          .item_name      = format_to_name,
4.          .option         = avformat_options,
5.          .version        = LIBAVUTIL_VERSION_INT,
6.          .child_next     = format_child_next,
7.          .child_class_iterate = format_child_class_iterate,
8.          .category       = AV_CLASS_CATEGORY_MUXER,
9.          .get_category   = get_category,
10. };

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AVOutputFormat

1. const AVOutputFormat ff_mp4_muxer = {
2.     .name              = "mp4",
3.     .long_name         = NULL_IF_CONFIG_SMALL("MP4 (MPEG-4 Part 14)"),
4.     .mime_type         = "video/mp4",
5.     .extensions        = "mp4",
6.     .priv_data_size    = sizeof(MOVMuxContext),
7.     .audio_codec       = AV_CODEC_ID_AAC,
8.     .video_codec       = CONFIG_LIBX264_ENCODER ?
9.                          AV_CODEC_ID_H264 : AV_CODEC_ID_MPEG4,
10.     .init              = mov_init,
11.     .write_header      = mov_write_header,
12.     .write_packet      = mov_write_packet,
13.     .write_trailer     = mov_write_trailer,
14.     .deinit            = mov_free,
15.     .flags             = AVFMT_GLOBALHEADER | AVFMT_ALLOW_FLUSH | AVFMT_TS_NEGATIVE,
16.     .codec_tag         = mp4_codec_tags_list,
17.     .check_bitstream   = mov_check_bitstream,
18.     .priv_class        = &mov_isobmff_muxer_class,
19. };

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demo

1. avformat_alloc_output_context2(&m_ic, NULL, NULL, file);
2. m_vs = avformat_new_stream(m_ic, NULL);
3. m_vs->codecpar->codec_tag = 0;
4. avcodec_parameters_from_context(m_vs->codecpar, m_vc);
5. av_dump_format(m_ic, 0, m_filename.c_str(), 1);
7. m_as = avformat_new_stream(m_ic, NULL);
8. m_as->codecpar->codec_tag = 0;
9. avcodec_parameters_from_context(m_as->codecpar, m_ac);
10. av_dump_format(m_ic, 0, m_filename.c_str(), 1);
12. int ret = avio_open(&m_ic->pb, m_filename.c_str(), AVIO_FLAG_WRITE);
13. ret = avformat_write_header(m_ic, NULL);
14. av_interleaved_write_frame(m_ic, pkt);
15. av_write_trailer(m_ic);
16. avio_closep(&m_ic->pb);
17. avformat_close_input(&m_ic);

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其他

ffmpeg 习惯记载

muxer_list.c 有个结构体为 muxer_list 是ffmpeg 支持的全部 AVOutputFormat。其他的类似，比如 codec_list。
allformat.c 是全部支持的 AVOutputFormat 界说的 extern。其他类似 alldevices,allcodecs,allfilters
avio.h 全部函数

1. const char *avio_find_protocol_name(const char *url);
2. int avio_check(const char *url, int flags);
3. int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options);
4. int avio_read_dir(AVIODirContext *s, AVIODirEntry **next);
5. int avio_close_dir(AVIODirContext **s);
6. void avio_free_directory_entry(AVIODirEntry **entry);
7. AVIOContext *avio_alloc_context(unsigned char *buffer, int buffer_size, int write_flag, void *opaque, 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));
8. void avio_context_free(AVIOContext **s);
9. void avio_w8(AVIOContext *s, int b);
10. void avio_write(AVIOContext *s, const unsigned char *buf, int size);
11. void avio_wl64(AVIOContext *s, uint64_t val);
12. void avio_wb64(AVIOContext *s, uint64_t val);
13. void avio_wl32(AVIOContext *s, unsigned int val);
14. void avio_wb32(AVIOContext *s, unsigned int val);
15. void avio_wl24(AVIOContext *s, unsigned int val);
16. void avio_wb24(AVIOContext *s, unsigned int val);
17. void avio_wl16(AVIOContext *s, unsigned int val);
18. void avio_wb16(AVIOContext *s, unsigned int val);
19. int avio_put_str(AVIOContext *s, const char *str);
20. int avio_put_str16le(AVIOContext *s, const char *str);
21. int avio_put_str16be(AVIOContext *s, const char *str);
22. void avio_write_marker(AVIOContext *s, int64_t time, enum AVIODataMarkerType type);
23. int64_t avio_seek(AVIOContext *s, int64_t offset, int whence);
24. int64_t avio_skip(AVIOContext *s, int64_t offset);
25. static av_always_inline int64_t avio_tell(AVIOContext *s){return avio_seek(s, 0, SEEK_CUR);}
26. int64_t avio_size(AVIOContext *s);
27. int avio_feof(AVIOContext *s);
28. int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
29. void avio_print_string_array(AVIOContext *s, const char *strings[]);
30. void avio_flush(AVIOContext *s);
31. int avio_read(AVIOContext *s, unsigned char *buf, int size);
32. int avio_read_partial(AVIOContext *s, unsigned char *buf, int size);
33. int          avio_r8  (AVIOContext *s);
34. unsigned int avio_rl16(AVIOContext *s);
35. unsigned int avio_rl24(AVIOContext *s);
36. unsigned int avio_rl32(AVIOContext *s);
37. uint64_t     avio_rl64(AVIOContext *s);
38. unsigned int avio_rb16(AVIOContext *s);
39. unsigned int avio_rb24(AVIOContext *s);
40. unsigned int avio_rb32(AVIOContext *s);
41. uint64_t     avio_rb64(AVIOContext *s);
42. int avio_get_str16le(AVIOContext *pb, int maxlen, char *buf, int buflen);
43. int avio_get_str16be(AVIOContext *pb, int maxlen, char *buf, int buflen);
44. int avio_open(AVIOContext **s, const char *url, int flags);
45. int avio_open2(AVIOContext **s, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options);
46. int avio_close(AVIOContext *s);
47. int avio_closep(AVIOContext **s);
48. int avio_open_dyn_buf(AVIOContext **s);
49. int avio_get_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
50. int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer);
51. const char *avio_enum_protocols(void **opaque, int output);
52. const AVClass *avio_protocol_get_class(const char *name);
53. int     avio_pause(AVIOContext *h, int pause);
54. int64_t avio_seek_time(AVIOContext *h, int stream_index, int64_t timestamp, int flags);
55. int avio_read_to_bprint(AVIOContext *h, struct AVBPrint *pb, size_t max_size);
56. int avio_accept(AVIOContext *s, AVIOContext **c);
57. int avio_handshake(AVIOContext *c);

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avformat.h 全部函数

1. void av_format_inject_global_side_data(AVFormatContext *s);
2. enum AVDurationEstimationMethod av_fmt_ctx_get_duration_estimation_method(const AVFormatContext* ctx);
3. unsigned avformat_version(void);
4. const char *avformat_configuration(void);
5. const char *avformat_license(void);
6. int avformat_network_init(void);
7. int avformat_network_deinit(void);
8. const AVOutputFormat *av_muxer_iterate(void **opaque);
9. const AVInputFormat *av_demuxer_iterate(void **opaque);
10. AVFormatContext *avformat_alloc_context(void);
11. void avformat_free_context(AVFormatContext *s);
12. const AVClass *avformat_get_class(void);
13. AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c);
14. int av_stream_add_side_data(AVStream *st, enum AVPacketSideDataType type, uint8_t *data, size_t size);
15. uint8_t *av_stream_new_side_data(AVStream *stream, enum AVPacketSideDataType type, size_t size);
16. uint8_t *av_stream_get_side_data(const AVStream *stream, enum AVPacketSideDataType type, size_t *size);
17. AVProgram *av_new_program(AVFormatContext *s, int id);
18. int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename);
19. const AVInputFormat *av_find_input_format(const char *short_name);
20. const AVInputFormat *av_probe_input_format(const AVProbeData *pd, int is_opened);
21. const AVInputFormat *av_probe_input_format2(const AVProbeData *pd, int is_opened, int *score_max);
22. const AVInputFormat *av_probe_input_format3(const AVProbeData *pd, int is_opened, int *score_ret);
23. int av_probe_input_buffer2(AVIOContext *pb, const AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size);
24. int av_probe_input_buffer(AVIOContext *pb, const AVInputFormat **fmt, const char *url, void *logctx, unsigned int offset, unsigned int max_probe_size);
25. int avformat_open_input(AVFormatContext **ps, const char *url, const AVInputFormat *fmt, AVDictionary **options);
26. int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options);
27. AVProgram *av_find_program_from_stream(AVFormatContext *ic, AVProgram *last, int s);
28. void av_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx);
29. int av_find_best_stream(AVFormatContext *ic, enum AVMediaType type, int wanted_stream_nb, int related_stream, const AVCodec **decoder_ret, int flags);
30. int av_read_frame(AVFormatContext *s, AVPacket *pkt);
31. int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags);
32. int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
33. int avformat_flush(AVFormatContext *s);
34. int av_read_play(AVFormatContext *s);
35. int av_read_pause(AVFormatContext *s);
36. void avformat_close_input(AVFormatContext **s);
37. int avformat_write_header(AVFormatContext *s, AVDictionary **options);
38. int avformat_init_output(AVFormatContext *s, AVDictionary **options);
39. int av_write_frame(AVFormatContext *s, AVPacket *pkt);
40. int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt);
41. int av_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame);
42. int av_interleaved_write_uncoded_frame(AVFormatContext *s, int stream_index, AVFrame *frame);
43. int av_write_uncoded_frame_query(AVFormatContext *s, int stream_index);
44. int av_write_trailer(AVFormatContext *s);
45. const AVOutputFormat *av_guess_format(const char *short_name, const char *filename, onst char *mime_type);
46. enum AVCodecID av_guess_codec(const AVOutputFormat *fmt, const char *short_name, const char *filename, const char *mime_type, enum AVMediaType type);
47. int av_get_output_timestamp(struct AVFormatContext *s, int stream, int64_t *dts, int64_t *wall);
48. void av_hex_dump(FILE *f, const uint8_t *buf, int size);
49. void av_hex_dump_log(void *avcl, int level, const uint8_t *buf, int size);
50. void av_pkt_dump2(FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st);
51. void av_pkt_dump_log2(void *avcl, int level, const AVPacket *pkt, int dump_payload, const AVStream *st);
52. enum AVCodecID av_codec_get_id(const struct AVCodecTag * const *tags, unsigned int tag);
53. unsigned int av_codec_get_tag(const struct AVCodecTag * const *tags, enum AVCodecID id);
54. int av_codec_get_tag2(const struct AVCodecTag * const *tags, enum AVCodecID id, unsigned int *tag);
55. int av_find_default_stream_index(AVFormatContext *s);
56. int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
57. const AVIndexEntry *avformat_index_get_entry(AVStream *st, int idx);
58. const AVIndexEntry *avformat_index_get_entry_from_timestamp(AVStream *st, int64_t wanted_timestamp, int flags);
59. int av_add_index_entry(AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags);
60. void av_url_split(char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url);
61. void av_dump_format(AVFormatContext *ic, int index, const char *url, int is_output);
62. int av_get_frame_filename2(char *buf, int buf_size, const char *path, int number, int flags);
63. int av_get_frame_filename(char *buf, int buf_size, const char *path, int number);
64. int av_filename_number_test(const char *filename);
65. int av_sdp_create(AVFormatContext *ac[], int n_files, char *buf, int size);
66. int av_match_ext(const char *filename, const char *extensions);
67. int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance);
68. const struct AVCodecTag *avformat_get_riff_video_tags(void);
69. const struct AVCodecTag *avformat_get_riff_audio_tags(void);
70. const struct AVCodecTag *avformat_get_mov_video_tags(void);
71. const struct AVCodecTag *avformat_get_mov_audio_tags(void);
72. AVRational av_guess_sample_aspect_ratio(AVFormatContext *format, AVStream *stream, AVFrame *frame);
73. AVRational av_guess_frame_rate(AVFormatContext *ctx, AVStream *stream, AVFrame *frame);
74. int avformat_match_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec);
75. int avformat_queue_attached_pictures(AVFormatContext *s);
76. int avformat_transfer_internal_stream_timing_info(const AVOutputFormat *ofmt, AVStream *ost, const AVStream *ist, enum AVTimebaseSource copy_tb);
77. AVRational av_stream_get_codec_timebase(const AVStream *st);

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