Here's some more evolution of the program which unfortunately segfaults.
the av_init_packet(pkt) call is the problem. I thought this was how I
should allocate the packet but I guess that function requires an already
initialised AVPacket structure. What is the reccommended way to
initially allocate an AVPacket ?
#include <iostream>
extern "C" {
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
}
using namespace std;
int main(int argc, char **argv)
{
if (argc <= 1) {
cout << "usage audio_convert <fielname>\n" << endl;
}
// initialise libavformat /libavcodec
avcodec_register_all();
av_register_all();
// data structures
AVFormatContext *pFormatCtx;
// open input file
av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL);
// get stream info
av_find_stream_info(pFormatCtx);
// dump the format
dump_format(pFormatCtx, 0, argv[1], false);
// get first audio stream
AVCodecContext *pCodecCtx;
int audioStream=-1;
for(int i=0; i<pFormatCtx->nb_streams; i++) {
pCodecCtx=pFormatCtx->streams[i]->codec;
if(pCodecCtx->codec_type == AVMEDIA_TYPE_AUDIO) {
audioStream=i;
break;
}
}
if(audioStream==-1) {
cout << "No audio stream found" << endl;
}
// try to find it's codec and open it
AVCodec *pCodec;
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL) {
cout << "can't find codec" << endl;
}
avcodec_open(pCodecCtx,pCodec);
cout << "got the codec for the input stream" << endl;
// now try to get packets of samples from the input stream...i.e.
decoding
AVPacket *pkt;
av_init_packet(pkt);
av_free(pkt);
// cleanup
av_close_input_file(pFormatCtx);
return 0;
}
_______________________________________________
libav-user mailing list
[email protected]
https://lists.mplayerhq.hu/mailman/listinfo/libav-user
