I have a DLL one of my applications uses to receive video from RTSP cameras. Under the hood, the DLL uses FFMPEG libs from this release zip :
ffmpeg-20141022-git-6dc99fd-win64-shared.7z We have a wide variety of cameras in house and most of them work just fine. However, on one particular Pelco Model Number: IXE20DN-OCP, I am unable to connect. I tested the camera and rtsp connection string on VLC and it connects to the camera just fine.
I found the connection string here : http://www.ispyconnect.com/man.aspx?n=Pelco
rtsp://IPADDRESS:554/1/stream1 Oddly, even if I leave the port off of VLC, it connects, so I'm guessing its the default RTSP port or that VLC tries a variety of things based on your input.
In any case, when I attempt to connect, I get an error from av_format_open_input. It returns a code of -135. When I looked in the error code list I didn't see that listed. For good measure, I printed out all the errors in error.h just to see what their values were.
DumpErrorCodes - Error Code : AVERROR_BSF_NOT_FOUND = -1179861752 DumpErrorCodes - Error Code : AVERROR_BUG = -558323010 DumpErrorCodes - Error Code : AVERROR_BUFFER_TOO_SMALL = -1397118274 DumpErrorCodes - Error Code : AVERROR_DECODER_NOT_FOUND = -1128613112 DumpErrorCodes - Error Code : AVERROR_DEMUXER_NOT_FOUND = -1296385272 DumpErrorCodes - Error Code : AVERROR_ENCODER_NOT_FOUND = -1129203192 DumpErrorCodes - Error Code : AVERROR_EOF = -541478725 DumpErrorCodes - Error Code : AVERROR_EXIT = -1414092869 DumpErrorCodes - Error Code : AVERROR_EXTERNAL = -542398533 DumpErrorCodes - Error Code : AVERROR_FILTER_NOT_FOUND = -1279870712 DumpErrorCodes - Error Code : AVERROR_INVALIDDATA = -1094995529 DumpErrorCodes - Error Code : AVERROR_MUXER_NOT_FOUND = -1481985528 DumpErrorCodes - Error Code : AVERROR_OPTION_NOT_FOUND = -1414549496 DumpErrorCodes - Error Code : AVERROR_PATCHWELCOME = -1163346256 DumpErrorCodes - Error Code : AVERROR_PROTOCOL_NOT_FOUND = -1330794744 DumpErrorCodes - Error Code : AVERROR_STREAM_NOT_FOUND = -1381258232 DumpErrorCodes - Error Code : AVERROR_BUG2 = -541545794 DumpErrorCodes - Error Code : AVERROR_UNKNOWN = -1313558101 DumpErrorCodes - Error Code : AVERROR_EXPERIMENTAL = -733130664 DumpErrorCodes - Error Code : AVERROR_INPUT_CHANGED = -1668179713 DumpErrorCodes - Error Code : AVERROR_OUTPUT_CHANGED = -1668179714 DumpErrorCodes - Error Code : AVERROR_HTTP_BAD_REQUEST = -808465656 DumpErrorCodes - Error Code : AVERROR_HTTP_UNAUTHORIZED = -825242872 DumpErrorCodes - Error Code : AVERROR_HTTP_FORBIDDEN = -858797304 DumpErrorCodes - Error Code : AVERROR_HTTP_NOT_FOUND = -875574520 DumpErrorCodes - Error Code : AVERROR_HTTP_OTHER_4XX = -1482175736 DumpErrorCodes - Error Code : AVERROR_HTTP_SERVER_ERROR = -1482175992 Nothing even close to -135. I did find this error, sort of on stack overflow, here runtime error when linking ffmpeg libraries in qt creator where the author claims it is a DLL loading problem error. I'm not sure what led him to think that, but I followed the advice and used the dependency walker (http://www.dependencywalker.com/) to checkout what dependencies it thought my DLL needed. It listed a few, but they were already provided in my install package.
To make sure it was picking them up, I manually removed them from the install and observed a radical change in program behavior(that being my DLL didn't load and start to run at all).
So, I've got a bit of init code :
void FfmpegInitialize() { av_lockmgr_register(&LockManagerCb); av_register_all(); LOG_DEBUG0("av_register_all returned\n"); } Then I've got my main open connection routine ...
int RTSPConnect(const char *URL, int width, int height, frameReceived callbackFunction) { int errCode =0; if ((errCode = avformat_network_init()) != 0) { LOG_ERROR1("avformat_network_init returned error code %d\n", errCode); } LOG_DEBUG0("avformat_network_init returned\n"); //Allocate space and setup the the object to be used for storing all info needed for this connection fContextReadFrame = avformat_alloc_context(); // free'd in the Close method if (fContextReadFrame == 0) { LOG_ERROR1("Unable to set rtsp_transport options. Error code = %d\n", errCode); return FFMPEG_OPTION_SET_FAILURE; } LOG_DEBUG1("avformat_alloc_context returned %p\n", fContextReadFrame); AVDictionary *opts = 0; if ((errCode = av_dict_set(&opts, "rtsp_transport", "tcp", 0)) < 0) { LOG_ERROR1("Unable to set rtsp_transport options. Error code = %d\n", errCode); return FFMPEG_OPTION_SET_FAILURE; } LOG_DEBUG1("av_dict_set returned %d\n", errCode); //open rtsp DumpErrorCodes(); if ((errCode = avformat_open_input(&fContextReadFrame, URL, NULL, &opts)) < 0) { LOG_ERROR2("Unable to open avFormat RF inputs. URL = %s, and Error code = %d\n", URL, errCode); LOG_ERROR2("Error Code %d = %s\n", errCode, errMsg(errCode)); // NOTE context is free'd on failure. return FFMPEG_FORMAT_OPEN_FAILURE; } ... To be sure I didn't misunderstand the error code I printed the error message from ffmpeg but the error isn't found and my canned error message is returned instead.
My next step was going to be hooking up wireshark on my connection attempt and on the VLC connection attempt and trying to figure out what differences(if any) are causing the problem and what I can do to ffmpeg to make it work. As I said, I've got a dozen other cameras in house that use RTSP and they work with my DLL. Some utilize usernames/passwords/etc as well(so I know that isn't the problem).
Also, my run logs :
FfmpegInitialize - av_register_all returned Open - Open called. Pointers valid, passing control. Rtsp::RtspInterface::Open - Rtsp::RtspInterface::Open called Rtsp::RtspInterface::Open - VideoSourceString(35) = rtsp://192.168.14.60:554/1/stream1 Rtsp::RtspInterface::Open - Base URL = (192.168.14.60:554/1/stream1) Rtsp::RtspInterface::Open - Attempting to open (rtsp://192.168.14.60:554/1/stream1) for WxH(320x240) video RTSPSetFormatH264 - RTSPSetFormatH264 RTSPConnect - Called LockManagerCb - LockManagerCb invoked for op 1 LockManagerCb - LockManagerCb invoked for op 2 RTSPConnect - avformat_network_init returned RTSPConnect - avformat_alloc_context returned 019E6000 RTSPConnect - av_dict_set returned 0 DumpErrorCodes - Error Code : AVERROR_BSF_NOT_FOUND = -1179861752 ... DumpErrorCodes - Error Code : AVERROR_HTTP_SERVER_ERROR = -1482175992 RTSPConnect - Unable to open avFormat RF inputs. URL = rtsp://192.168.14.60:554/1/stream1, and Error code = -135 RTSPConnect - Error Code -135 = No Error Message Available I'm going to move forward with wireshark but would like to know the origin of the -135 error code from ffmpeg. When I look at the code if 'ret' is getting set to -135, it must be happening as a result of the return code from a helper method and not directly in the avformat_open_input method.
https://www.ffmpeg.org/doxygen/2.5/libavformat_2utils_8c_source.html#l00398
After upgrading to the latest daily ffmpeg build, I get data on wireshark. Real Time Streaming Protocol :
Request: SETUP rtsp://192.168.14.60/stream1/track1 RTSP/1.0\r\n Method: SETUP URL: rtsp://192.168.14.60/stream1/track1 Transport: RTP/AVP/TCP;unicast;interleaved=0-1 CSeq: 3\r\n User-Agent: Lavf56.31.100\r\n \r\n The response to that is the first 'error' that I can detect in the initiation.
Response: RTSP/1.0 461 Unsupported Transport\r\n Status: 461 CSeq: 3\r\n Date: Sun, Jan 04 1970 16:03:05 GMT\r\n \r\n I'm going to guess that... it means the transport we selected was unsupported. I quick check of the code reveals I picked 'tcp'. Looking through the reply to the DESCRIBE command, it appears :
Media Protocol: RTP/AVP Further, when SETUP is issued by ffmpeg, it specifies :
Transport: RTP/AVP/TCP;unicast;interleaved=0-1 I'm going to try, on failure here to pick another transport type and see how that works. Still don't know where the -135 comes from.