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我正在使用FFMPEG來解碼來自IP Camera的H264流。有很多相機,所以我用FFMPEG多線程。FFMPEG:多線程解碼死鎖?
我註冊多線程與FFMPEG通過下面的代碼
static int lockmgr(void **mtx, enum AVLockOp op)
{
switch (op)
{
case AV_LOCK_CREATE:
*mtx = malloc(sizeof(pthread_mutex_t));
if (!*mtx)
return 1;
return !!pthread_mutex_init((pthread_mutex_t*)*mtx, NULL);
case AV_LOCK_OBTAIN:
return !!pthread_mutex_lock((pthread_mutex_t*)*mtx);
case AV_LOCK_RELEASE:
return !!pthread_mutex_unlock((pthread_mutex_t*)*mtx);
case AV_LOCK_DESTROY:
pthread_mutex_destroy((pthread_mutex_t*)*mtx);
free(*mtx);
return 0;
}
return 1;
}
av_lockmgr_register(lockmgr)
在每個連接到網絡攝像機螺紋,用於從網絡攝像機解碼H264流的代碼是下面
int DecodeStream()
{
try
{
InitForH264Stream();
int bytesDecoded = 0;
int frameFinished = 0;
while (commonGlobal->settings.iPCameraSettigs.isRunningThreadRequestVideo[rtpHeader->cameraInd])
{
while (_packet->size > 0)
{
// Decode the next chunk of data
bytesDecoded = avcodec_decode_video2(rtpHeader->pCodecCtx, rtpHeader->pFrame,
&frameFinished, _packet);
// Was there an error?
if (bytesDecoded < 0)
{
if (rtpHeader->packetPointer != NULL)
{
_packet->data = rtpHeader->packetPointer;
rtpHeader->packetPointer = NULL;
av_free_packet(_packet);
}
return RS_NOT_OK;
}
_packet->size -= bytesDecoded;
_packet->data += bytesDecoded;
if (rtpHeader->packetPointer != NULL && _packet->size == 0)
{
_packet->data = rtpHeader->packetPointer;
rtpHeader->packetPointer = NULL;
av_free_packet(_packet);
}
if (frameFinished)
{
return RS_OK;
}
// Did we finish the current frame? Then we can return
}
do
{
try
{
av_init_packet(_packet);
rtpHeader->th->Reset();
int ret = AVERROR(EAGAIN);
while (AVERROR(EAGAIN) == ret)
ret = av_read_frame(pFormatCtx, _packet);
if (ret < 0)
{
if (ret == AVERROR(AVERROR_EOF) || (pFormatCtx->pb && pFormatCtx->pb->eof_reached))
{
sprintf(strErr, "Error end of file line %d", __LINE__);
}
if (pFormatCtx->pb && pFormatCtx->pb->error)
{
sprintf(strErr, "Error end of file line %d", __LINE__);
}
_packet->data = NULL;
return RS_NOT_OK;
}
if (_packet->stream_index != rtpHeader->videoStreamInd)
av_free_packet(_packet);
else
rtpHeader->packetPointer = _packet->data;
}
catch (...)
{
_packet->data = NULL;
return RS_NOT_OK;
}
} while (_packet->stream_index != rtpHeader->videoStreamInd);
}
}
catch (...)
{
_packet = NULL;
commonGlobal->WriteRuntimeLogs("ReceiveRTPBlock() threw an Exception");
UnInitForH264Stream();
return RS_NOT_OK;
}
}
VOID UnInitForH264Stream()
{
if (rtpHeader.pCodecCtx != NULL)
avcodec_close(rtpHeader.pCodecCtx);
if (pFormatCtx != NULL)
av_close_input_file(pFormatCtx);
if (rtpHeader.th != NULL)
{
delete rtpHeader.th;
rtpHeader.th = NULL;
}
if (rtpHeader.pFrame != NULL)
avcodec_free_frame(&rtpHeader.pFrame);
if (RGBFrame != NULL)
{
avcodec_free_frame(&RGBFrame);
RGBFrame = NULL;
}
if (ConversionContext != NULL)
{
sws_freeContext(ConversionContext);
ConversionContext = NULL;
}
if (rgbBuffer != NULL)
{
av_free(rgbBuffer);
rgbBuffer = NULL;
}
}
當函數
avcodec_decode_video2()
拋出一個異常時,我遇到了一個死鎖,然後當調用UnInitForH264Stream()
在線時程序被鎖死我已修好,也許功能avcodec_decode_video2()
工作正確(不拋出異常)。但是現在有時我在解碼時遇到了死鎖,但是我不知道哪個函數導致了死鎖。因爲很難重現這個錯誤。
有人可以告訴我在我的代碼中是否存在潛在的死鎖?
非常感謝!
謝謝!此代碼是摘要,主代碼按照您所說的「將它們移動到您的流開始的中央同步位置」來實現。你能解釋一下我的代碼和上面顯示的鎖的實現之間有什麼區別嗎? – TTGroup 2014-11-06 06:28:52
我想刪除*這裏:if(!* mtx)。你也不需要!!在pthread函數前面。 !通常是C語言的「投擲指針」。我認爲它會返回1,如果pthread函數返回0將指示失敗。我不是100%關於這個 – Eric 2014-11-06 06:43:07
nvm,!!應該沒問題,它會爲所有非0值返回1 – Eric 2014-11-06 06:49:23