How to read an specified frame from an MPEG-TS video file?
Marcus Nascimento
marcus.cps at gmail.com
Mon Nov 4 07:50:40 PST 2013
Yashil,
Thanks very much for that.
My real intention is to be notified when the playback reaches a given frame
number, instead of doing seek.
But even though, it is going to be very useful on solving another issue in
a near future.
Thanks again,
Marcus
On Mon, Nov 4, 2013 at 3:57 AM, Yashil <yashil1 at yahoo.com> wrote:
> Marcus Nascimento wrote
> > Hi Yashil,
> >
> > I'm very interested in this solution too.
> > I believe you are a bit ahead of me.
> > Please, let me know if you find a good solution.
> >
> > If I manage to do it, I'll let you know.
> >
> > Thanks very much,
> > Marcus
>
> Here is my sample code. It grabs two frames from given video file and
> displays it by opencv. The first frame seek is done by given frame number
> and the second frame seek is done by given time position. It works for
> several codecs in my tests but I have not been able to make it work for
> mpeg2-ts files yet.
>
> MyGstFrameCap1.cpp
>
> /**********************************************************************/
> // gstreamer includes and libraries
> #include <gst/gst.h>
> #include <gst/app/gstappsink.h>
> #pragma comment( lib, "gstreamer-1.0.lib" )
> #pragma comment( lib, "glib-2.0.lib" )
> #pragma comment( lib, "gobject-2.0.lib" )
> #pragma comment( lib, "gstapp-1.0.lib" )
>
> /**********************************************************************/
> // opencv includes and libraries
> #include <opencv2/opencv.hpp>
> #ifdef _DEBUG
> #pragma comment( lib, "comctl32" )
> #pragma comment( lib, "opencv_core246d" )
> #pragma comment( lib, "opencv_highgui246d" )
> #ifndef _DLL
> #pragma comment( lib, "zlibd" )
> #pragma comment( lib, "IlmImfd" )
> #pragma comment( lib, "libjasperd" )
> #pragma comment( lib, "libjpegd" )
> #pragma comment( lib, "libpngd" )
> #pragma comment( lib, "libtiffd" )
> #endif
> #else
> #pragma comment( lib, "comctl32" )
> #pragma comment( lib, "opencv_core246" )
> #pragma comment( lib, "opencv_highgui246" )
> #ifndef _DLL
> #pragma comment( lib, "zlib" )
> #pragma comment( lib, "IlmImf" )
> #pragma comment( lib, "libjasper" )
> #pragma comment( lib, "libjpeg" )
> #pragma comment( lib, "libpng" )
> #pragma comment( lib, "libtiff" )
> #endif
> #endif
>
> /**********************************************************************/
> void MyfCopyRGBbuf2CvMat( cv::Mat& oMatFrameInp, unsigned char *pDataInp )
> {
> int nDi = 0;
> for( int nRi = 0; nRi < oMatFrameInp.rows; nRi++ )
> {
> for( int nCi = 0; nCi < oMatFrameInp.cols; nCi++ )
> {
> oMatFrameInp.data[oMatFrameInp.step[0] * nRi +
> oMatFrameInp.step[1] * nCi
> + 2] = pDataInp[nDi++]; // R
> oMatFrameInp.data[oMatFrameInp.step[0] * nRi +
> oMatFrameInp.step[1] * nCi
> + 1] = pDataInp[nDi++]; // G
> oMatFrameInp.data[oMatFrameInp.step[0] * nRi +
> oMatFrameInp.step[1] * nCi
> + 0] = pDataInp[nDi++]; // B
> }
> }
> }
>
> /**********************************************************************/
> void MyfDispGstSampleInOpenCvWin( GstSample *pstGstSampleInp, gchar
> *szgWinTitle )
> {
> if( !pstGstSampleInp ) { g_print( "*** Error: Could not make
> snapshot (may
> be due to eos)."); return; }
>
> GstCaps *pstGstCaps1;
> pstGstCaps1 = gst_sample_get_caps( pstGstSampleInp );
> if( !pstGstCaps1 ) { g_print( "*** Error: gst_sample_get_caps
> fails to get
> sample cpas." ); return; }
>
> GstStructure *pstGstSt1;
> pstGstSt1 = gst_caps_get_structure( pstGstCaps1, 0 );
>
> gint nFrameWidth, nFrameHeight;
> gboolean nGboolRes1;
> nGboolRes1 = gst_structure_get_int( pstGstSt1, "width",
> &nFrameWidth );
> nGboolRes1 |= gst_structure_get_int( pstGstSt1, "height",
> &nFrameHeight );
> if( !nGboolRes1 ) { g_print( "*** Error: gst_structure_get_int
> fails to get
> snapshot dimension."); return; }
>
> GstBuffer *pstGstBuffer1;
> pstGstBuffer1 = gst_sample_get_buffer( pstGstSampleInp );
> GstMapInfo stGstMapInfo1;
> gst_buffer_map( pstGstBuffer1, &stGstMapInfo1, GST_MAP_READ );
>
> cv::Mat oMatTstFrame;
> oMatTstFrame = cv::Mat::zeros( nFrameHeight, nFrameWidth, CV_8UC3
> );
> MyfCopyRGBbuf2CvMat( oMatTstFrame, stGstMapInfo1.data );
>
> gst_buffer_unmap( pstGstBuffer1, &stGstMapInfo1 );
>
> cv::namedWindow( szgWinTitle, CV_WINDOW_AUTOSIZE );
> cv::imshow( szgWinTitle, oMatTstFrame );
> }
>
>
> //********************************************************************************
> int main( int argc, char *argv[] )
> {
> gst_init( &argc, &argv );
>
> // Describe pipeline
> gchar *szgPipelineDescStr1;
> szgPipelineDescStr1 = g_strdup_printf( "uridecodebin
> uri=\"file:///D:/QuickTimeSample.mov\" ! videoconvert ! videoscale !
> appsink
> name=sink caps=\"video/x-raw,format=RGB\"" ); // Works for both frame and
> time seek
> //szgPipelineDescStr1 = g_strdup_printf( "uridecodebin
> uri=\"file:///D:/mpts_out.ts\" ! videoconvert ! videoscale ! appsink
> name=sink caps=\"video/x-raw,format=RGB\"" ); // NOT works for both frame
> and time seek
>
> // Create pipeline
> GstElement *pstGstElemPipeline1;
> GError *pstGErr1 = NULL;
> pstGstElemPipeline1 = gst_parse_launch( szgPipelineDescStr1,
> &pstGErr1 );
> if( pstGErr1 != NULL )
> {
> g_print( "could not construct pipeline: %s\n",
> pstGErr1->message );
> g_error_free( pstGErr1 ); return( -1 );
> }
>
> // Set to GST_STATE_PAUSED
> GstStateChangeReturn nStateChgRet;
> nStateChgRet = gst_element_set_state( pstGstElemPipeline1,
> GST_STATE_PAUSED
> );
> if( nStateChgRet == GST_STATE_CHANGE_FAILURE ) goto Cleanup;
> nStateChgRet = gst_element_get_state( pstGstElemPipeline1, NULL,
> NULL, 5 *
> GST_SECOND );
> if( nStateChgRet == GST_STATE_CHANGE_FAILURE ) goto Cleanup;
>
> // Set desired frame number to be displayed
> gint64 nDesiredMediaPosFrameNum = 120;
>
> // Init required variables
> GstElement *pstGstElemAppSink1;
> pstGstElemAppSink1 = gst_bin_get_by_name( GST_BIN(
> pstGstElemPipeline1 ),
> "sink" );
> gboolean nGboolRes1;
> char *szgWinTitle;
>
> // Seek by GST_FORMAT_DEFAULT
> nGboolRes1 = gst_element_seek_simple( pstGstElemPipeline1,
> GST_FORMAT_DEFAULT, (GstSeekFlags) ( GST_SEEK_FLAG_ACCURATE |
> GST_SEEK_FLAG_FLUSH ), nDesiredMediaPosFrameNum );
> if( !nGboolRes1 ) { g_print( "*** Error: gst_element_seek_simple by
> GST_FORMAT_DEFAULT failed!\n"); }
>
> // Read sample
> GstSample *pstGstSample1;
> pstGstSample1 = gst_app_sink_pull_preroll( (GstAppSink *)
> pstGstElemAppSink1 ); // or g_signal_emit_by_name( pstGstElemAppSink1,
> "pull-preroll", &pstGstSample1, NULL );
>
> // Display sample
> szgWinTitle = g_strdup_printf( "Frame #%lld",
> nDesiredMediaPosFrameNum );
> MyfDispGstSampleInOpenCvWin( pstGstSample1, szgWinTitle );
>
>
> // Set desired position by time to be displayed
> gint64 nDesiredMediaPosNanoSec = 1000 * GST_MSECOND;
>
> // Seek by GST_FORMAT_DEFAULT
> nGboolRes1 = gst_element_seek_simple( pstGstElemPipeline1,
> GST_FORMAT_TIME,
> (GstSeekFlags) ( GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_FLUSH ),
> nDesiredMediaPosNanoSec );
> if( !nGboolRes1 ) { g_print( "*** Error: gst_element_seek_simple by
> GST_FORMAT_TIME failed!\n"); }
>
> // Read sample
> GstSample *pstGstSample2;
> pstGstSample2 = gst_app_sink_pull_preroll( (GstAppSink *)
> pstGstElemAppSink1 );
>
> // Display sample
> szgWinTitle = g_strdup_printf( "Time %" GST_TIME_FORMAT,
> GST_TIME_ARGS(
> nDesiredMediaPosNanoSec ) );
> MyfDispGstSampleInOpenCvWin( pstGstSample2, szgWinTitle );
>
> Cleanup:
> gst_element_set_state( pstGstElemPipeline1, GST_STATE_NULL );
> gst_object_unref( pstGstElemPipeline1 );
>
> g_print( "Press any key to finish...\n");
> cvWaitKey( 0 );
> return( 0 );
> }
>
>
> Note:
> Include directories:
>
> D:\gstreamer\1.0\x86\include\gstreamer-1.0;D:\gstreamer\1.0\x86\include\glib-2.0;D:\gstreamer\1.0\x86\lib\glib-2.0\include;D:\opencv246\build\include\
>
> Library directories:
> d:\opencv246\build\x86\vc11\staticlib;D:\gstreamer\1.0\x86\lib
>
>
>
>
> --
> View this message in context:
> http://gstreamer-devel.966125.n4.nabble.com/How-to-read-an-specified-frame-from-an-MPEG-TS-video-file-tp4663005p4663079.html
> Sent from the GStreamer-devel mailing list archive at Nabble.com.
> _______________________________________________
> gstreamer-devel mailing list
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> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
--
Marcus Nascimento
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