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• FFMPEG error with avformat_open_input returning -135

  28 avril 2015, par LawfulEvil

  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.

• Revision 60e01c6530 : Account for eob cost in the RTC mode decision process This commit accounts for

  3 avril 2015, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_pickmode.c

  
  
  Account for eob cost in the RTC mode decision process

  This commit accounts for the transform block end of coefficient flag
  cost in the RTC mode decision process. This allows a more precise
  rate estimate. It also turns on the model to block sizes up to 32x32.
  The test sequences shows about 3% - 5% speed penalty for speed -6.
  The average compression performance improvement for speed -6 is
  1.58% in PSNR. The compression gains for hard clips like jimredvga,
  mmmoving, and tacomascmv at low bit-rate range are 1.8%, 2.1%, and
  3.2%, respectively.

  Change-Id : Ic2ae211888e25a93979eac56b274c6e5ebcc21fb

• Grand Unified Theory of Compact Disc

  1er février 2013, par Multimedia Mike — General

  This is something I started writing about a decade ago (and I almost certainly have some of it wrong), back when compact discs still had a fair amount of relevance. Back around 2002, after a few years investigating multimedia technology, I took an interest in compact discs of all sorts. Even though there may seem to be a wide range of CD types, I generally found that they’re all fundamentally the same. I thought I would finally publishing something, incomplete though it may be.

  Physical Perspective
  There are a lot of ways to look at a compact disc. First, there’s the physical format, where a laser detects where pits/grooves have disturbed the smooth surface (a.k.a. lands). A lot of technical descriptions claim that these lands and pits on a CD correspond to ones and zeros. That’s not actually true, but you have to decide what level of abstraction you care about, and that abstraction is good enough if you only care about the discs from a software perspective.

  Grand Unified Theory (Software Perspective)
  Looking at a disc from a software perspective, I have generally found it useful to view a CD as a combination of a 2 main components :

  • table of contents (TOC)
  • a long string of sectors, each of which is 2352 bytes long

  I like to believe that’s pretty much all there is to it. All of the information on a CD is stored as a string of sectors that might be chopped up into a series of anywhere from 1-99 individual tracks. The exact sector locations where these individual tracks begin are defined in the TOC.

  Audio CDs (CD-DA / Red Book)
  The initial purpose for the compact disc was to store digital audio. The strange sector size of 2352 bytes is an artifact of this original charter. “CD quality audio”, as any multimedia nerd knows, is formally defined as stereo PCM samples that are each 16 bits wide and played at a frequency of 44100 Hz.
  

  (44100 audio frames / 1 second) * (2 samples / audio frame) * 
    (16 bits / 1 sample) * (1 byte / 8 bits) = 176,400 bytes / second
  (176,400 bytes / 1 second) / (2352 bytes / 1 sector) = 75
  

  75 is the number of sectors required to store a single second of CD-quality audio. A single sector stores 1/75th of a second, or a ‘frame’ of audio (though I think ‘frame’ gets tossed around at all levels when describing CD formats).

  The term “red book” is thrown around in relation to audio CDs. There is a series of rainbow books that define various optical disc standards and the red book describes audio CDs.

  Basic Data CD-ROMs (Mode 1 / Yellow Book)
  Somewhere along the line, someone decided that general digital information could be stored on these discs. Hence, the CD-ROM was born. The standard model above still applies– TOC and string of 2352-byte sectors. However, it’s generally only useful to have a single track on a CD-ROM. Thus, the TOC only lists a single track. That single track can easily span the entire disc (something that would be unusual for a typical audio CD).

  While the model is mostly the same, the most notable difference between and audio CD and a plain CD-ROM is that, while each sector is 2352 bytes long, only 2048 bytes are used to store actual data payload. The remaining bytes are used for synchronization and additional error detection/correction.

  At least, the foregoing is true for mode 1 / form 1 CD-ROMs (which are the most common). “Mode 1″ CD-ROMs are defined by a publication called the yellow book. There is also mode 1 / form 2. This forgoes the additional error detection and correction afforded by form 1 and dedicates 2336 of the 2352 sector bytes to the data payload.

  CD-ROM XA (Mode 2 / Green Book)
  From a software perspective, these are similar to mode 1 CD-ROMs. There are also 2 forms here. The first form gives a 2048-byte data payload while the second form yields a 2324-byte data payload.

  Video CD (VCD / White Book)
  These are CD-ROM XA discs that carry MPEG-1 video and audio data.

  Photo CD (Beige Book)
  This is something I have never personally dealt with. But it’s supposed to conform to the CD-ROM XA standard and probably fits into my model. It seems to date back to early in the CD-ROM era when CDs were particularly cost prohibitive.

  Multisession CDs (Blue Book)
  Okay, I admit that this confuses me a bit. Multisession discs allow a user to burn multiple sessions to a single recordable disc. I.e., burn a lump of data, then burn another lump at a later time, and the final result will look like all the lumps were recorded as the same big lump. I remember this being incredibly useful and cost effective back when recordable CDs cost around US$10 each (vs. being able to buy a spindle of 100 CD-Rs for US$10 or less now). Studying the cdrom.h file for the Linux OS, I found a system call named CDROMMULTISESSION that returns the sector address of the start of the last session. If I were to hypothesize about how to make this fit into my model, I might guess that the TOC has some hint that the disc was recorded in multisession (which needs to be decided up front) and the CDROMMULTISESSION call is made to find the last session. Or it could be that a disc read initialization operation always leads off with the CDROMMULTISESSION query in order to determine this.

  I suppose I could figure out how to create a multisession disc with modern software, or possibly dig up a multisession disc from 15+ years ago, and then figure out how it should be read.

  CD-i
  This type puzzles my as well. I do have some CD-i discs and I thought that I could read them just fine (the last time I looked, which was many years ago). But my research for this blog post has me thinking that I might not have been seeing the entire picture when I first studied my CD-i samples. I was able to see some of the data, but sources indicate that only proper CD-i hardware is able to see all of the data on the disc (apparently, the TOC doesn’t show all of the sectors on disc).

  Hybrid CDs (Data + Audio)
  At some point, it became a notable selling point for an audio CD to have a data track with bonus features. Even more common (particularly in the early era of CD-ROMs) were computer and console games that used the first track of a disc for all the game code and assets and the remaining tracks for beautifully rendered game audio that could also be enjoyed outside the game. Same model : TOC points to the various tracks and also makes notes about which ones are data and which are audio.

  There seems to be 2 distinct things described above. One type is the mixed mode CD which generally has the data in the first track and the audio in tracks 2..n. Then there is the enhanced CD, which apparently used multisession recording and put the data at the end. I think that the reasoning for this is that most audio CD player hardware would only read tracks from the first session and would have no way to see the data track. This was a positive thing. By contrast, when placing a mixed-mode CD into an audio player, the data track would be rendered as nonsense noise.

  Subchannels
  There’s at least one small detail that my model ignores : subchannels. CDs can encode bits of data in subchannels in sectors. This is used for things like CD-Text and CD-G. I may need to revisit this.

  In Summary
  There’s still a lot of ground to cover, like how those sectors might be formatted to show something useful (e.g., filesystems), and how the model applies to other types of optical discs. Sounds like something for another post.