gistfile1.txt

// ffm_console.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

extern "C" {
#include "ffmpeg/inttypes.h"
#include "ffmpeg/include/libavutil/error.h"
#include "ffmpeg/include/libavutil/samplefmt.h"
#include "ffmpeg/include/libavcodec/avcodec.h"
#include "ffmpeg/include/libavformat/avformat.h"
#include "ffmpeg/include/libavutil/file.h"
#include "ffmpeg/include/libavutil/frame.h"
#include "ffmpeg/include/libswresample/swresample.h"
#include "ffmpeg/include/libavutil/channel_layout.h"
}

AVDictionaryEntry *tag = NULL; 
AVFormatContext *pFormatCtx;
AVOutputFormat *pOutputFormatCtx;
AVCodecContext *codecctx = NULL;
AVCodec *aCodec;
AVPacket avpkt;
FILE * f;
static SwrContext * swrctx = NULL;
AVFrame *decoded_frame = NULL;

int _tmain(int argc, _TCHAR* argv[])
{
	int errcode;
	int duration = 0;
	int loop_point = 0;
	int total_samples = 0x7fffffff;
	int loop_samples = 0;
		
	avcodec_register_all();
	av_register_all();	
				
	const char *filename = "input.flv";
	
	if ((errcode = avformat_open_input(&pFormatCtx, filename, NULL, NULL)) < 0)
	{
        char errDescr[4096];
        av_strerror(errcode, errDescr, 4096);
		return -1;
	} 
	
	//
	// find audio stream
	//
	int audioStreamIdx = 0;
	for (int i=0;i<pFormatCtx->nb_streams;i++)
	{
		if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)
		{
			audioStreamIdx = i;
			break;
		}	
	}

	av_init_packet(&avpkt);
	av_read_frame(pFormatCtx, &avpkt);

	int header_size = avpkt.pos;
	int full_packet_size = avpkt.size;

	avformat_find_stream_info(pFormatCtx,NULL);
	codecctx = pFormatCtx->streams[audioStreamIdx]->codec; 

	double temp = (double)(pFormatCtx->duration / 1000.0) * (double)(codecctx->sample_rate / 1000.0);
	total_samples = (int)temp;

	aCodec = avcodec_find_decoder(pFormatCtx->streams[audioStreamIdx]->codec->codec_id);
	if (aCodec == NULL)
		return -1;
			
	int res = avcodec_open2(codecctx, aCodec, NULL);
	if (res)
		return -1;

		
	// ----------------------------------------------------------
	// decode part

	uint8_t sample_buffer[0x10000*4];
	int samples = 0;
	
	int framecount = 0;
	int got_frame = 0;
	uint8_t *out = sample_buffer;
	
	FILE * outfile = fopen("output.raw", "wb");

	int channel_layout = av_get_default_channel_layout(codecctx->channels); 
	swrctx = swr_alloc_set_opts(swrctx, channel_layout, AV_SAMPLE_FMT_S16, codecctx->sample_rate, channel_layout, codecctx->sample_fmt, codecctx->sample_rate,	0,	NULL);
	if (!swrctx || swr_init(swrctx) < 0)
	{
		avcodec_close(codecctx);
		return -1;
	}

	int frame = 0;
	int bytes_written = 0;

	while (true)
	{
		int samples = 0;
		int consumed_data = 0;
		
		if (avpkt.size == 0)
		{
			frame = av_read_frame(pFormatCtx, &avpkt);
			if (frame != 0)
			{
				fclose(outfile);
				swr_free(&swrctx);
				return 0;
			}
		}

		if (!decoded_frame)
		{
			if (!(decoded_frame = av_frame_alloc()))
				return -1;
		}

		got_frame = 0;
		
		consumed_data = avcodec_decode_audio4(codecctx, decoded_frame, &got_frame, &avpkt);
		if (consumed_data < 0)
		{
			avpkt.size = 0;
			continue;
		}

		int total_sample_space = 0;
		if (got_frame)
		{
			memset(sample_buffer,0,0x40000);
			samples = swr_convert(swrctx, &out, decoded_frame->nb_samples, (const uint8_t**)decoded_frame->extended_data, decoded_frame->nb_samples);
			total_sample_space = av_samples_get_buffer_size(NULL, codecctx->channels, decoded_frame->nb_samples,codecctx->sample_fmt,1);
			fwrite(sample_buffer, 1, total_sample_space, outfile);
			bytes_written += samples * (2*codecctx->channels);
		}

		avpkt.size -= consumed_data;
		avpkt.data += consumed_data;
	}

	av_frame_unref(decoded_frame);
	fclose(outfile);
	swr_free(&swrctx);
	return 0;
}