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Obtain fourcc when AVStream is network stream

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The `codec_tag` is only available when opening a file from disk. If `AVStream` is a network stream then `fourcc` must be obtained using `codec_id`. I have tested the following scenarios:
1) Open a `.mp4` file and verify that `codec_tag` is returned (old behavior)
2) Open a `rtsp` stream and verify that `codec_fourcc` is returned (Tested with a MJPEG, H264 and H265 stream)
This commit is contained in:
Peter Rekdal Sunde 2018-09-29 19:43:01 +02:00 committed by Peter Rekdal Sunde
parent 1059735bfb
commit 042c486b68
1 changed files with 57 additions and 2 deletions
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59
modules/videoio/src/cap_ffmpeg_impl.hpp
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@ -48,6 +48,7 @@
#include <algorithm>
#include <limits>
#define OPENCV_FOURCC(c1, c2, c3, c4) (((c1) & 255) + (((c2) & 255) << 8) + (((c3) & 255) << 16) + (((c4) & 255) << 24))
#define CALC_FFMPEG_VERSION(a,b,c) ( a<<16 | b<<8 | c )
#if defined _MSC_VER && _MSC_VER >= 1200
@ -350,6 +351,41 @@ struct AVInterruptCallbackMetadata
int timeout;
};
// https://github.com/opencv/opencv/pull/12693#issuecomment-426236731
static
inline const char* _opencv_avcodec_get_name(AVCodecID id)
{
#if LIBAVCODEC_VERSION_MICRO >= 100 \
&& LIBAVCODEC_BUILD >= CALC_FFMPEG_VERSION(53, 47, 100)
return avcodec_get_name(id);
#else
const AVCodecDescriptor *cd;
AVCodec *codec;
if (id == AV_CODEC_ID_NONE)
{
return "none";
}
cd = avcodec_descriptor_get(id);
if (cd)
{
return cd->name;
}
codec = avcodec_find_decoder(id);
if (codec)
{
return codec->name;
}
codec = avcodec_find_encoder(id);
if (codec)
{
return codec->name;
}
return "unknown_codec";
#endif
}
static
inline void _opencv_ffmpeg_free(void** ptr)
{
@ -1121,6 +1157,10 @@ double CvCapture_FFMPEG::getProperty( int property_id ) const
{
if( !video_st ) return 0;
double codec_tag = 0;
AVCodecID codec_id = AV_CODEC_ID_NONE;
const char* codec_fourcc = NULL;
switch( property_id )
{
case CV_FFMPEG_CAP_PROP_POS_MSEC:
@ -1139,10 +1179,25 @@ double CvCapture_FFMPEG::getProperty( int property_id ) const
return get_fps();
case CV_FFMPEG_CAP_PROP_FOURCC:
#if LIBAVFORMAT_BUILD > 4628
return (double)video_st->codec->codec_tag;
codec_id = video_st->codec->codec_id;
codec_tag = (double) video_st->codec->codec_tag;
#else
return (double)video_st->codec.codec_tag;
codec_id = video_st->codec.codec_id;
codec_tag = (double)video_st->codec.codec_tag;
#endif
if(codec_tag || codec_id == AV_CODEC_ID_NONE)
{
return codec_tag;
}
codec_fourcc = _opencv_avcodec_get_name(codec_id);
if(!codec_fourcc || strlen(codec_fourcc) < 4 || strcmp(codec_fourcc, "unknown_codec") == 0)
{
return codec_tag;
}
return (double) OPENCV_FOURCC(codec_fourcc[0], codec_fourcc[1], codec_fourcc[2], codec_fourcc[3]);
case CV_FFMPEG_CAP_PROP_SAR_NUM:
return _opencv_ffmpeg_get_sample_aspect_ratio(ic->streams[video_stream]).num;
case CV_FFMPEG_CAP_PROP_SAR_DEN: