1 为什么需要在FFmpeg中设置http请求参数

使用ffmpeg拉取远程服务器直播流时，一般我们都是使用以下的命令行

ffmpeg -i http://39.134.115.163:8080/PLTV/88888910/224/3221225767/index.m3u8 -c:a copy -c:v copy H:\视频录制\cctv5live.mp4

远程服务器如果没有对客户端请求进行任何验证，这种方式就不会出现问题，一旦远程服务器对客户端的请求进行了验证，我们需要在命令行中添加ffmpeg一些内置的http参数选项进行设置，以便我们可以通过服务器的权限验证。

1.1 ffmpeg源码http.c中所的相关http参数

在ffmpeg的源码http.c中我们可以找到相关的http选项，

源码链接如下：https://ffmpeg.org/doxygen/4.1/http_8c_source.html

有关的代码片段如下：

 static const AVOption options[] = {
     { "seekable", "control seekability of connection", OFFSET(seekable), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, D },
     { "chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, E },
     { "http_proxy", "set HTTP proxy to tunnel through", OFFSET(http_proxy), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "headers", "set custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "content_type", "set a specific content type for the POST messages", OFFSET(content_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "user_agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D },
     { "referer", "override referer header", OFFSET(referer), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D },
 #if FF_API_HTTP_USER_AGENT
     { "user-agent", "use the \"user_agent\" option instead", OFFSET(user_agent_deprecated), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D|AV_OPT_FLAG_DEPRECATED },
 #endif
     { "multiple_requests", "use persistent connections", OFFSET(multiple_requests), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D | E },
     { "post_data", "set custom HTTP post data", OFFSET(post_data), AV_OPT_TYPE_BINARY, .flags = D | E },
     { "mime_type", "export the MIME type", OFFSET(mime_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
     { "http_version", "export the http response version", OFFSET(http_version), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
     { "cookies", "set cookies to be sent in applicable future requests, use newline delimited Set-Cookie HTTP field value syntax", OFFSET(cookies), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D },
     { "icy", "request ICY metadata", OFFSET(icy), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, D },
     { "icy_metadata_headers", "return ICY metadata headers", OFFSET(icy_metadata_headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
     { "icy_metadata_packet", "return current ICY metadata packet", OFFSET(icy_metadata_packet), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
     { "metadata", "metadata read from the bitstream", OFFSET(metadata), AV_OPT_TYPE_DICT, {0}, 0, 0, AV_OPT_FLAG_EXPORT },
     { "auth_type", "HTTP authentication type", OFFSET(auth_state.auth_type), AV_OPT_TYPE_INT, { .i64 = HTTP_AUTH_NONE }, HTTP_AUTH_NONE, HTTP_AUTH_BASIC, D | E, "auth_type"},
     { "none", "No auth method set, autodetect", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_NONE }, 0, 0, D | E, "auth_type"},
     { "basic", "HTTP basic authentication", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_BASIC }, 0, 0, D | E, "auth_type"},
     { "send_expect_100", "Force sending an Expect: 100-continue header for POST", OFFSET(send_expect_100), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
     { "location", "The actual location of the data received", OFFSET(location), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "offset", "initial byte offset", OFFSET(off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
     { "end_offset", "try to limit the request to bytes preceding this offset", OFFSET(end_off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
     { "method", "Override the HTTP method or set the expected HTTP method from a client", OFFSET(method), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
     { "reconnect", "auto reconnect after disconnect before EOF", OFFSET(reconnect), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
     { "reconnect_at_eof", "auto reconnect at EOF", OFFSET(reconnect_at_eof), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
     { "reconnect_streamed", "auto reconnect streamed / non seekable streams", OFFSET(reconnect_streamed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
     { "reconnect_delay_max", "max reconnect delay in seconds after which to give up", OFFSET(reconnect_delay_max), AV_OPT_TYPE_INT, { .i64 = 120 }, 0, UINT_MAX/1000/1000, D },
     { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
     { "resource", "The resource requested by a client", OFFSET(resource), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
     { "reply_code", "The http status code to return to a client", OFFSET(reply_code), AV_OPT_TYPE_INT, { .i64 = 200}, INT_MIN, 599, E},
     { NULL }
 };

上述选项：

  • seekable：控制连接的可查找性；
  • chunked_post：对请求使用分块传输代码；
  • http_proxy：http代理；
  • headers：设置自定义HTTP Header，可以覆盖内置的默认Header；
  • content_type：为POST消息设置特定的内容类型；
  • user_agent：覆盖默认的User-Agent；
  • referer：覆盖默认的referer；
  • multiple_requests：使用持久连接；
  • post_data：自定义的http请求的post数据；
  • mime_type：导出MIME类型；
  • http_version：导出http响应版本；
  • cookies：自定义cookies；
  • icy：请求icy元数据；
  • icy_metadata_headers：返回icy headers；
  • icy_metadata_packet：返回icy元数据包；
  • metadata：从比特流读取的元数据；
  • auth_type：Http验证类型；
  • reconnect：EOF前断开连接后自动重新连接；
  • reconnect_at_eof：在EOF时自动连接；
  • reconnect_streamed：自动重新连接流式/不可查找流；
  • reconnect_delay_max：重新连接的最大延迟；

其中我们常用的http请求参数大致是以下几个：

  • http_proxy
  • headers
  • user_agent
  • referer
  • cookies
  • reconnect_delay_max

1.2 参数的使用

1.2.1 在命令行中的使用

比如在上述命令中加上user_agent请求参数，命令行如下

ffmpeg -user_agent "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0" -i http://39.134.115.163:8080/PLTV/88888910/224/3221225767/index.m3u8 -c:a copy -c:v copy H:\视频录制\cctv5live.mp4

1.2.2 在代码开发中的使用

我们可以通过以下代码设置请求参数，如

AVDictionary* input_format_context_options = NULL;
av_dict_set(&input_format_context_options, "user_agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0", 0);
int ret = avformat_open_input(&pFormatCtx, url, 0, &input_format_context_options);