主要参考FFMPEG里面的apiexample.c以及output_example.c编写
int main(int argc, char **argv)
{
char *filename = "d:\\1.asf";
char *outfilename = "d:\\test.mp4";
AVFormatContext *pFormatCtxDec, *pFormatCtxEnc;
AVCodecContext *pCodecCtxDec, *pCodecCtxEnc;
AVCodec *pCodecDec, *pCodecEnc;
AVFrame *pFrameDec, *pFrameEnc;
AVOutputFormat *pOutputFormat;
AVStream *video_st;
int i, videoStream;
int outbuf_size;
uint8_t *outbuf;
AVPacket packet;
int frameFinished,frames=0;
int out_size;
// Register all formats and codecs
av_register_all();
// Open video file
if(av_open_input_file(&pFormatCtxDec, filename, NULL, 0, NULL)!=0)
return ; // Couldn't open file
// Retrieve stream information
if(av_find_stream_info(pFormatCtxDec)<0)
return ; // Couldn't find stream information
// Find the first video stream
videoStream=-1;
for(i=0; i<pFormatCtxDec->nb_streams; i++) {
if(pFormatCtxDec->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO)
{
videoStream=i;
break;
}
}
if(videoStream==-1)
return ; // Didn't find a video stream
// Get a pointer to the codec context for the video stream
pCodecCtxDec=pFormatCtxDec->streams[videoStream]->codec;
// Find the decoder for the video stream
pCodecDec=avcodec_find_decoder(pCodecCtxDec->codec_id);
if(pCodecDec==NULL)
return ; // Codec not found
// Inform the codec that we can handle truncated bitstreams -- i.e.,
// bitstreams where frame boundaries can fall in the middle of packets
//if(pCodecDec->capabilities & CODEC_CAP_TRUNCATED)
// pCodecCtxDec->flags|=CODEC_FLAG_TRUNCATED;
// Open codec
if(avcodec_open(pCodecCtxDec, pCodecDec)<0)
return ; // Could not open codec
// Allocate video frame
pFrameDec = avcodec_alloc_frame();
if(pFrameDec == NULL)
return ;
// auto detect the output format from the name. default is mpeg.
pOutputFormat = guess_format(NULL, outfilename, NULL);
if (pOutputFormat == NULL)
return;
// allocate the output media context
pFormatCtxEnc = av_alloc_format_context();
if (pFormatCtxEnc == NULL)
return;
pFormatCtxEnc->oformat = pOutputFormat;
sprintf(pFormatCtxEnc->filename, "%s", outfilename);
video_st = av_new_stream(pFormatCtxEnc, 0); // 0 for video
pCodecCtxEnc = video_st->codec;
pCodecCtxEnc->codec_id = pOutputFormat->video_codec;
pCodecCtxEnc->codec_type = CODEC_TYPE_VIDEO;
// put sample parameters
pCodecCtxEnc->bit_rate = 200000;
// resolution must be a multiple of two
pCodecCtxEnc->width = pCodecCtxDec->width;
pCodecCtxEnc->height = pCodecCtxDec->height;
// frames per second
pCodecCtxEnc->time_base.den = 25;
pCodecCtxEnc->time_base.num = 1;
pCodecCtxEnc->pix_fmt = PIX_FMT_YUV420P;
pCodecCtxEnc->gop_size = 12;
if (pCodecCtxEnc->codec_id == CODEC_ID_MPEG1VIDEO){
pCodecCtxEnc->mb_decision=2;
}
// some formats want stream headers to be seperate
if(!strcmp(pFormatCtxEnc->oformat->name, "mp4") || !strcmp(pFormatCtxEnc->oformat->name, "mov") || !strcmp(pFormatCtxEnc->oformat->name, "3gp"))
pCodecCtxEnc->flags |= CODEC_FLAG_GLOBAL_HEADER;
// set the output parameters (must be done even if no parameters).
if (av_set_parameters(pFormatCtxEnc, NULL) < 0) {
return;
}
// find the video encoder
pCodecEnc = avcodec_find_encoder(pCodecCtxEnc->codec_id);
if (pCodecEnc == NULL)
return;
// open it
if (avcodec_open(pCodecCtxEnc, pCodecEnc) < 0) {
return;
}
if (!(pFormatCtxEnc->oformat->flags & AVFMT_RAWPICTURE)) {
outbuf_size = 500000;
outbuf = av_malloc(outbuf_size);
}
pFrameEnc= avcodec_alloc_frame();
// open the output file, if needed
if (!(pOutputFormat->flags & AVFMT_NOFILE)) {
if (url_fopen(&pFormatCtxEnc->pb, outfilename, URL_WRONLY) < 0) {
fprintf(stderr, "Could not open '%s'\n", filename);
return;
}
}
// write the stream header, if any
av_write_header(pFormatCtxEnc);
// Read frames and save frames to disk
while(av_read_frame(pFormatCtxDec, &packet)>=0)
{
// Is this a packet from the video stream?
if(packet.stream_index==videoStream)
{
// Decode video frame
avcodec_decode_video(pCodecCtxDec, pFrameDec, &frameFinished, packet.data, packet.size);
// Did we get a video frame?
if(frameFinished)
{
frames++;
pFrameEnc->data[0] = pFrameDec->data[0];
pFrameEnc->data[1] = pFrameDec->data[1];
pFrameEnc->data[2] = pFrameDec->data[2];
pFrameEnc->linesize[0] = pFrameDec->linesize[0];
pFrameEnc->linesize[1] = pFrameDec->linesize[1];
pFrameEnc->linesize[2] = pFrameDec->linesize[2];
if (pFormatCtxEnc->oformat->flags & AVFMT_RAWPICTURE) {
AVPacket pkt;
av_init_packet(&pkt);
pkt.flags |= PKT_FLAG_KEY;
pkt.stream_index= video_st->index;
pkt.data= (uint8_t *)pFrameEnc;
pkt.size= sizeof(AVPicture);
av_write_frame(pFormatCtxEnc, &pkt);
} else {
// encode the image
out_size = avcodec_encode_video(pCodecCtxEnc, outbuf, outbuf_size, pFrameEnc);
// if zero size, it means the image was buffered
if (out_size != 0) {
AVPacket pkt;
av_init_packet(&pkt);
pkt.pts= pCodecCtxEnc->coded_frame->pts;
if(pCodecCtxEnc->coded_frame->key_frame)
pkt.flags |= PKT_FLAG_KEY;
pkt.stream_index= video_st->index;
pkt.data= outbuf;
pkt.size= out_size;
// write the compressed frame in the media file
av_write_frame(pFormatCtxEnc, &pkt);
}
}
}
}
// Free the packet that was allocated by av_read_frame
av_free_packet(&packet);
}
// get the delayed frames
for(; out_size; i++) {
out_size = avcodec_encode_video(pCodecCtxEnc, outbuf, outbuf_size, NULL);
if (out_size != 0) {
AVPacket pkt;
av_init_packet(&pkt);
pkt.pts= pCodecCtxEnc->coded_frame->pts;
if(pCodecCtxEnc->coded_frame->key_frame)
pkt.flags |= PKT_FLAG_KEY;
pkt.stream_index= video_st->index;
pkt.data= outbuf;
pkt.size= out_size;
// write the compressed frame in the media file
av_write_frame(pFormatCtxEnc, &pkt);
}
}
// Close the codec
avcodec_close(pCodecCtxDec);
avcodec_close(pCodecCtxEnc);
// Free the YUV frame
av_free(pFrameDec);
av_free(pFrameEnc);
av_free(outbuf);
// write the trailer, if any
av_write_trailer(pFormatCtxEnc);
// free the streams
for(i = 0; i < pFormatCtxEnc->nb_streams; i++) {
av_freep(&pFormatCtxEnc->streams[i]->codec);
av_freep(&pFormatCtxEnc->streams[i]);
}
if (!(pOutputFormat->flags & AVFMT_NOFILE)) {
url_fclose(&pFormatCtxEnc->pb);
}
av_free(pFormatCtxEnc);
// Close the video file
av_close_input_file(pFormatCtxDec);
av_free_static();
}
