ffplayer.c FFmpeg测试例子 最近在做android上应用

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

void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) {
	FILE *pFile;
	char szFilename[32];
	int  y;
	
	// Open file
	sprintf(szFilename, "frame%d.ppm", iFrame);
	pFile=fopen(szFilename, "wb");
	if(pFile==NULL)
		return;
	
	// Write header
	fprintf(pFile, "P6\n%d %d\n255\n", width, height);
	
	// Write pixel data
	for(y=0; y<height; y++)
		fwrite(pFrame->data[0]+y*pFrame->linesize[0], 1, width*3, pFile);
	
	// Close file
	fclose(pFile);
}

int main(int argc, char *argv[]) {
	int i;
	AVCodecContext *pCodecCtx;
	AVFrame *pFrame;
	AVCodec *pCodec;
	AVFormatContext *pFormatCtx;
	
	av_register_all();
	
	// Open video file
	if(av_open_input_file(&pFormatCtx, argv[1], NULL, 0, NULL)!=0)
		return -1; // Couldn't open file
	// Retrieve stream information
	if(av_find_stream_info(pFormatCtx)<0)
		return -1; // Couldn't find stream information
	
	// Find the first video stream
	int videoStream=-1;
	for(i=0; i<pFormatCtx->nb_streams; i++)
		if(pFormatCtx->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO) {
			videoStream=i;
			break;
		}
	if(videoStream==-1)
		return -1; // Didn't find a video stream
	
	// Get a pointer to the codec context for the video stream
	pCodecCtx=pFormatCtx->streams[videoStream]->codec;
	
	// Find the decoder for the video stream
	pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
	if(pCodec==NULL) {
		fprintf(stderr, "Unsupported codec!\n");
		return -1; // Codec not found
	}
	// Open codec
	if(avcodec_open(pCodecCtx, pCodec)<0)
		return -1; // Could not open codec
	
	// Allocate video frame
	pFrame=avcodec_alloc_frame();
	
	// Allocate an AVFrame structure
	AVFrame *pFrameRGB=avcodec_alloc_frame();
	if(pFrameRGB==NULL)
		return -1;
	
	uint8_t *buffer;
	int numBytes;
	// Determine required buffer size and allocate buffer
	numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
								pCodecCtx->height);
	buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
	
	// Assign appropriate parts of buffer to image planes in pFrameRGB
	// Note that pFrameRGB is an AVFrame, but AVFrame is a superset
	// of AVPicture
	avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
				   pCodecCtx->width, pCodecCtx->height);
	
	int frameFinished;
	AVPacket packet;
	
	i=0;
	while(av_read_frame(pFormatCtx, &packet)>=0) {
		// Is this a packet from the video stream?
		if(packet.stream_index==videoStream) {
			// Decode video frame
			avcodec_decode_video(pCodecCtx, pFrame, &frameFinished,
								 packet.data, packet.size);
			
			// Did we get a video frame?
			if(frameFinished) {
				// Convert the image from its native format to RGB
				img_convert((AVPicture *)pFrameRGB, PIX_FMT_RGB24, 
							(AVPicture*)pFrame, pCodecCtx->pix_fmt, 
							pCodecCtx->width, pCodecCtx->height);
				
				// Save the frame to disk
				if(++i<=5)
					SaveFrame(pFrameRGB, pCodecCtx->width, 
							  pCodecCtx->height, i);
			}
		}
		
		// Free the packet that was allocated by av_read_frame
		av_free_packet(&packet);
	}
	
	// Free the RGB image
	av_free(buffer);
	av_free(pFrameRGB);
	
	// Free the YUV frame
	av_free(pFrame);
	
	// Close the codec
	avcodec_close(pCodecCtx);
	
	// Close the video file
	av_close_input_file(pFormatCtx);
	
	return 0;
}