利用FFmpeg将mkv视频转换为H.264

const char* SRC_FILE = "Titanic.mkv";
const char* OUT_FILE = "Titanic.h264";
const char* OUT_FMT_FILE = "Titanic.mp4";
int _tmain(int argc, _TCHAR* argv[])
{
av_register_all();
AVFormatContext* pFormat = NULL;
if (avformat_open_input(&pFormat, SRC_FILE, NULL, NULL) < 0)
{
return 0;
}
AVCodecContext* video_dec_ctx = NULL;
AVCodec* video_dec = NULL;
if (avformat_find_stream_info(pFormat, NULL) < 0)
{
return 0;
}
av_dump_format(pFormat, 0, SRC_FILE, 0);
video_dec_ctx = pFormat->streams[0]->codec;
video_dec = avcodec_find_decoder(video_dec_ctx->codec_id);
if (avcodec_open2(video_dec_ctx, video_dec, NULL) < 0)
{
return 0;
}

AVFormatContext* pOFormat = NULL;
AVOutputFormat* ofmt = NULL;
if (avformat_alloc_output_context2(&pOFormat, NULL, NULL, OUT_FILE) < 0)
{
return 0;
}
ofmt = pOFormat->oformat;
if (avio_open(&(pOFormat->pb), OUT_FILE, AVIO_FLAG_READ_WRITE) < 0)
{
return 0;
}
AVCodecContext *video_enc_ctx = NULL;
AVCodec *video_enc = NULL;
video_enc = avcodec_find_encoder(AV_CODEC_ID_H264);
AVStream *video_st = avformat_new_stream(pOFormat, video_enc);
if (!video_st)
return 0;
video_enc_ctx = video_st->codec;
video_enc_ctx->width = video_dec_ctx->width;
video_enc_ctx->height = video_dec_ctx->height;
video_enc_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
video_enc_ctx->time_base.num = 1;
video_enc_ctx->time_base.den = 25;
video_enc_ctx->bit_rate = video_dec_ctx->bit_rate;
video_enc_ctx->gop_size = 250;
video_enc_ctx->max_b_frames = 10;

video_enc_ctx->qmin = 10;
video_enc_ctx->qmax = 51;
if (avcodec_open2(video_enc_ctx, video_enc, NULL) < 0)
{
printf("编码器打开失败！\n");
return 0;
}
printf("Output264video Information====================\n");
av_dump_format(pOFormat, 0, OUT_FILE, 1);
printf("Output264video Information====================\n");

//mp4 file
AVFormatContext* pMp4Format = NULL;
AVOutputFormat* pMp4OFormat = NULL;
if (avformat_alloc_output_context2(&pMp4Format, NULL, NULL, OUT_FMT_FILE) < 0)
{
return 0;
}
pMp4OFormat = pMp4Format->oformat;
if (avio_open(&(pMp4Format->pb), OUT_FMT_FILE, AVIO_FLAG_READ_WRITE) < 0)
{
return 0;
}
for (int i = 0; i < pFormat->nb_streams; i++) {
AVStream *in_stream = pFormat->streams[i];
AVStream *out_stream = avformat_new_stream(pMp4Format, in_stream->codec->codec);
if (!out_stream) {
return 0;
}
int ret = 0;
ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
if (ret < 0) {
fprintf(stderr, "Failed to copy context from input to output stream codec context\n");
return 0;
}
out_stream->codec->codec_tag = 0;
if (pMp4Format->oformat->flags & AVFMT_GLOBALHEADER)
out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
av_dump_format(pMp4Format, 0, OUT_FMT_FILE, 1);
if (avformat_write_header(pMp4Format, NULL) < 0)
{
return 0;
}
av_opt_set(video_enc_ctx->priv_data, "preset", "superfast", 0);
av_opt_set(video_enc_ctx->priv_data, "tune", "zerolatency", 0);
avformat_write_header(pOFormat, NULL);
AVPacket *pkt = new AVPacket();
av_init_packet(pkt);
AVFrame *pFrame = av_frame_alloc();// avcodec_alloc_frame();
int ts = 0;
while (1)
{
if (av_read_frame(pFormat, pkt) < 0)
{
avio_close(pOFormat->pb);
av_write_trailer(pMp4Format);
avio_close(pMp4Format->pb);
delete pkt;
return 0;
}
if (pkt->stream_index == 0)
{

int got_picture = 0, ret = 0;
ret = avcodec_decode_video2(video_dec_ctx, pFrame, &got_picture, pkt);
if (ret < 0)
{
delete pkt;
return 0;
}
pFrame->pts = pFrame->pkt_pts;//ts++;
if (got_picture)
{
AVPacket *tmppkt = new AVPacket;
av_init_packet(tmppkt);
int size = video_enc_ctx->width*video_enc_ctx->height * 3 / 2;
char* buf = new char[size];
memset(buf, 0, size);
tmppkt->data = (uint8_t*)buf;
tmppkt->size = size;
ret = avcodec_encode_video2(video_enc_ctx, tmppkt, pFrame, &got_picture);
if (ret < 0)
{
avio_close(pOFormat->pb);
delete buf;
return 0;
}
if (got_picture)
{
//ret = av_interleaved_write_frame(pOFormat, tmppkt);
AVStream *in_stream = pFormat->streams[pkt->stream_index];
AVStream *out_stream = pMp4Format->streams[pkt->stream_index];

tmppkt->pts = av_rescale_q_rnd(tmppkt->pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
tmppkt->dts = av_rescale_q_rnd(tmppkt->dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
tmppkt->duration = av_rescale_q(tmppkt->duration, in_stream->time_base, out_stream->time_base);
tmppkt->pos = -1;
ret = av_interleaved_write_frame(pMp4Format, tmppkt);
if (ret < 0)
return 0;
delete tmppkt;
delete buf;
}
}
//avcodec_free_frame(&pFrame);
}
else if (pkt->stream_index == 1)
{
AVStream *in_stream = pFormat->streams[pkt->stream_index];
AVStream *out_stream = pMp4Format->streams[pkt->stream_index];

pkt->pts = av_rescale_q_rnd(pkt->pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
pkt->dts = av_rescale_q_rnd(pkt->dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
pkt->duration = av_rescale_q(pkt->duration, in_stream->time_base, out_stream->time_base);
pkt->pos = -1;
if (av_interleaved_write_frame(pMp4Format, pkt) < 0)
return 0;
}
}
av_frame_free(&pFrame);
return 0;
}