libav problem - minimal code snippet

#include "libavcodec/avcodec.h"
#include "libavformat/avformat.h"

int main(int argc, char *argv[])
{
    av_register_all();
    av_log_set_level(AV_LOG_DEBUG);

    AVFormatContext* format_context = NULL;

    avformat_open_input(&format_context, argv[1], NULL, NULL);

    avformat_find_stream_info(format_context, NULL);

    int stream_no = av_find_best_stream(format_context,AVMEDIA_TYPE_AUDIO,-1,-1,NULL,0);
    AVStream* stream = format_context->streams[stream_no];

    AVCodec* codec = avcodec_find_decoder(stream->codec->codec_id);
    avcodec_open2(stream->codec, codec, NULL);

    AVPacket input_packet;
    av_init_packet(&input_packet);
    input_packet.data = NULL;
    input_packet.size = 0;

    av_read_frame(format_context, &input_packet);

    int decoded;
    AVFrame* frame = avcodec_alloc_frame();

    AVCodecContext* codec_context = stream->codec;
    avcodec_decode_audio4(codec_context, frame, &decoded, &input_packet);
}


///////////////////////////////////////////////////////////////////////////////
// OUTPUT
///////////////////////////////////////////////////////////////////////////////
// [flac @ 0x991040] Probed with size=2048 and score=50
// [mjpeg @ 0x994b80] marker=d8 avail_size_in_buf=43302
// [mjpeg @ 0x994b80] marker parser used 0 bytes (0 bits)
// [mjpeg @ 0x994b80] marker=e0 avail_size_in_buf=43300
// [mjpeg @ 0x994b80] marker parser used 16 bytes (128 bits)
// [mjpeg @ 0x994b80] marker=db avail_size_in_buf=43282
// [mjpeg @ 0x994b80] index=0
// [mjpeg @ 0x994b80] qscale[0]: 3
// [mjpeg @ 0x994b80] marker parser used 67 bytes (536 bits)
// [mjpeg @ 0x994b80] marker=db avail_size_in_buf=43213
// [mjpeg @ 0x994b80] index=1
// [mjpeg @ 0x994b80] qscale[1]: 6
// [mjpeg @ 0x994b80] marker parser used 67 bytes (536 bits)
// [mjpeg @ 0x994b80] marker=c0 avail_size_in_buf=43144
// [mjpeg @ 0x994b80] sof0: picture: 500x494
// [mjpeg @ 0x994b80] component 0 2:2 id: 0 quant:0
// [mjpeg @ 0x994b80] component 1 1:1 id: 1 quant:1
// [mjpeg @ 0x994b80] component 2 1:1 id: 2 quant:1
// [mjpeg @ 0x994b80] pix fmt id 22111100
// [mjpeg @ 0x994b80] marker parser used 17 bytes (136 bits)
// [mjpeg @ 0x994b80] marker=c4 avail_size_in_buf=43125
// [mjpeg @ 0x994b80] class=0 index=0 nb_codes=12
// [mjpeg @ 0x994b80] marker parser used 31 bytes (248 bits)
// [mjpeg @ 0x994b80] marker=c4 avail_size_in_buf=43092
// [mjpeg @ 0x994b80] class=1 index=0 nb_codes=251
// [mjpeg @ 0x994b80] marker parser used 181 bytes (1448 bits)
// [mjpeg @ 0x994b80] marker=c4 avail_size_in_buf=42909
// [mjpeg @ 0x994b80] class=0 index=1 nb_codes=12
// [mjpeg @ 0x994b80] marker parser used 31 bytes (248 bits)
// [mjpeg @ 0x994b80] marker=c4 avail_size_in_buf=42876
// [mjpeg @ 0x994b80] class=1 index=1 nb_codes=251
// [mjpeg @ 0x994b80] marker parser used 181 bytes (1448 bits)
// [mjpeg @ 0x994b80] escaping removed 202 bytes
// [mjpeg @ 0x994b80] marker=da avail_size_in_buf=42693
// [mjpeg @ 0x994b80] component: 0
// [mjpeg @ 0x994b80] component: 1
// [mjpeg @ 0x994b80] component: 2
// [mjpeg @ 0x994b80] marker parser used 42490 bytes (339914 bits)
// [mjpeg @ 0x994b80] marker=d9 avail_size_in_buf=0
// [mjpeg @ 0x994b80] mjpeg decode frame unused 0 bytes
// [flac @ 0x991040] max_analyze_duration reached
// [flac @ 0x992fc0] invalid sync code
// [flac @ 0x992fc0] invalid frame header
// [flac @ 0x992fc0] decode_frame() failed