Recherche avancée

Sur d’autres sites (4715)

• ffmpeg:When receiving a udp network video stream, it is found that the values of the received packets PTS and DTS change abnormally

  24 octobre 2022, par watermelon_seven

  I am using the ffmpeg source code to receive the udp network video stream, but there is a problem with this video stream. Occasionally, the audio and video packets dts and pts jump at the same time, that is, from a large value to a difference of dozens of times. Very small value, I want to use a solution to solve this problem in the code, but can't think of it. Hope you can help me, thanks !

  


  The following is a process of writing to the buffer to be decoded after receiving the video packet when I receive the network stream. The decoding is done by the video decoding thread, which is only responsible for receiving the stream and writing the buffer to be decoded.

  


      //read video package&#xA;    if(pAvPacket->stream_index == pThis->m_iVideoStreamIndex)&#xA;    {&#xA;        std::cout&lt;&lt;"Video_Packet_DTS: "&lt;dts&lt;&lt;"   Video_Packet_PTS: "&lt;pts&lt;/Video frame rate assignment&#xA;        if(pThis->m_pVideoTimeBase->num > 0 &amp;&amp; pAvPacket->duration > 0)&#xA;            pThis->m_iVideoFPS = (pThis->m_pVideoTimeBase->den / pThis->m_pVideoTimeBase->num) / pAvPacket->duration;&#xA;&#xA;        if(pThis->m_iDecodeMode == DECODE_MODE_ONLY_CURRENT_COLLECTION)&#xA;            pThis->m_videoDecodeThreadState = THREAD_NEED_STOP;     //stop the thread&#xA;        else&#xA;            pThis->m_videoDecodeThreadState = THREAD_NEED_RUN;      //make the thread run&#xA;&#xA;        if(pThis->m_iMultiMediaType != MULTI_MEDIA_TYPE_FILE&#xA;                &amp;&amp; pAvPacket->flags == AV_PKT_FLAG_KEY)&#xA;        {&#xA;                pThis->m_bIsFindIFrame = YTRUE;&#xA;        }&#xA;&#xA;        VideoFramesCount &#x2B;&#x2B;;&#xA;        pThis->m_iReadVideoPacketCount &#x2B;&#x2B;;&#xA;        if(pThis->m_iDecodeMode != DECODE_MODE_ONLY_CHECK_NET &amp;&amp; pThis->m_iDecodeMode != DECODE_MODE_AUDIO &amp;&amp; pThis->m_bIsFindIFrame)&#xA;            YGlobCircleBufferWrite<avpacket>(pThis->m_videoPacketBuffer, &amp;pAvPacket, 1);&#xA;        else&#xA;            av_packet_unref(pAvPacket);&#xA;        pAvPacket = YNULL;&#xA;    }&#xA;</avpacket>

  


  The following is the information printed when the code is run :

  


  Video_Packet_DTS: 8590470992   Video_Packet_PTS: 8590470992
Video_Packet_DTS: 8590474592   Video_Packet_PTS: 8590474592
Video_Packet_DTS: 8590478192   Video_Packet_PTS: 8590478192
Video_Packet_DTS: 8590481792   Video_Packet_PTS: 8590481792
Video_Packet_DTS: 550800   Video_Packet_PTS: 550800
Video_Packet_DTS: 554400   Video_Packet_PTS: 554400
Video_Packet_DTS: 558000   Video_Packet_PTS: 558000
Video_Packet_DTS: 561600   Video_Packet_PTS: 561600
Video_Packet_DTS: 565200   Video_Packet_PTS: 565200


  


  and the error message is printed :

  


  [h264 @ 04fea380] non-existing PPS 0 referenced
[h264 @ 04fea380] decode_slice_header error
[h264 @ 04fea380] no frame!
[swscaler @ 19b04600] Warning: data is not aligned! This can lead to a speed loss
[mp3float @ 04feadc0] overread, skip -6 enddists: -2 -2
[mpegts @ 04fcbf40] DTS 550800 < 8590481792 out of order
[mp3float @ 04feadc0] overread, skip -7 enddists: -6 -6
[mp3float @ 04feadc0] overread, skip -5 enddists: -2 -2


  


  I am so obsessed with their pts because when I synchronize audio and video, I will use their pts for synchronization. If the pts are too different, the video will be stuck when playing the video. I don't know how to avoid

  


• libavformat/riffec : Zero-initialize channels in ff_get_wav_header

  9 septembre 2022, par Will Cassella

  libavformat/riffec : Zero-initialize channels in ff_get_wav_header
  Clang's static analyzer complains that leaving the  variable
  
  uninitialized could lead to a code path where the uninitialized value is
  
  written to  at the end of this function.
  
  This patch simply zero-initializes that variable to avoid that.
  Signed-off-by : Will Cassella <cassew@google.com>
  
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] libavformat/riffdec.c

• avutil/dict : Error out in case of key == NULL

  14 septembre 2022, par Andreas Rheinhardt

  avutil/dict : Error out in case of key == NULL
  Up until now, using NULL as key in av_dict_get() on a non-empty
  
  AVDictionary would crash ; using NULL as key in av_dict_set()
  
  would also crash for a non-empty AVDictionary unless AV_DICT_MULTIKEY
  
  was set ; in case the dictionary was initially empty or AV_DICT_MULTIKEY
  
  was set, it was even possible for av_dict_set() to succeed when
  
  adding a NULL key, namely when one uses a value != NULL and
  
  the AV_DICT_DONT_STRDUP_VAL flag. Using av_dict_get() on such
  
  an AVDictionary will usually lead to crashes, though.
  Fix this by actually checking for key in both functions ; error out
  
  if they are NULL.
  While just at it, also stop relying on av_strdup(NULL) to return NULL
  
  in av_dict_set().
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavutil/dict.c
  • [DH] libavutil/tests/dict.c