ffmpeg合并视频api实现

#define __STDC_CONSTANT_MACROS

#ifdef _WIN32
//Windows
extern "C"
{
#include "libavformat/avformat.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavformat/avformat.h>
#ifdef __cplusplus
};
#endif
#endif

/*
FIX: H.264 in some container format (FLV, MP4, MKV etc.) need
"h264_mp4toannexb" bitstream filter (BSF)
*Add SPS,PPS in front of IDR frame
*Add start code ("0,0,0,1") in front of NALU
H.264 in some container (MPEG2TS) don't need this BSF.
*/
//'1': Use H.264 Bitstream Filter
#define USE_H264BSF 0

/*
FIX:AAC in some container format (FLV, MP4, MKV etc.) need
"aac_adtstoasc" bitstream filter (BSF)
*/
//'1': Use AAC Bitstream Filter
#define USE_AACBSF 0

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>

#include <libswscale/swscale.h>

- (void)cancatVideo {
AVOutputFormat *ofmt = NULL;
//Input AVFormatContext and Output AVFormatContext
AVFormatContext *ofmt_ctx = NULL;
AVFormatContext *ifmt_ctx_array[30] = {0};
AVPacket pkt;
char in_filename[500]={0};
char out_filename[500]={0};
int ret, i;
int frame_index=0;
NSString *fileName;
NSString *videoPath;
NSMutableArray *input_array = [[NSMutableArray alloc] init];
for (id object in _array) {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
videoPath = [NSString stringWithFormat:@"%@/%@",[paths objectAtIndex:0],[object objectForKey:@"video_id"]];
[input_array addObject:videoPath];
}

//    NSString *input_str= @"resource.bundle/1450954312111_c.mp4";
//    NSString *input_str2= @"resource.bundle/1450925430841_c.mp4";
//    NSString *input_str3= @"resource.bundle/1451049906063_c.mp4";
av_register_all();
i=0;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *output_nsstr = [NSString stringWithFormat:@"%@/haoba.mp4",[paths objectAtIndex:0]];
sprintf(out_filename,"%s",[output_nsstr UTF8String]);
for (id object in input_array) {
NSString *input_nsstr = object;
sprintf(in_filename,"%s",[input_nsstr UTF8String]);
if(![[NSFileManager defaultManager] fileExistsAtPath:input_nsstr]) {
printf( "文件不存在\n");
} else {
printf( "文件是存在的\n");
}
if ((ret = avformat_open_input(&ifmt_ctx_array[i], in_filename, 0, 0)) < 0) {
printf( "Could not open input file.%s",in_filename);
goto end;
}
if ((ret = avformat_find_stream_info(ifmt_ctx_array[i], 0)) < 0) {
printf( "Failed to retrieve input stream information");
goto end;
}
i++;
}
//Output
avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename);
if (!ofmt_ctx) {
printf( "Could not create output context\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ofmt = ofmt_ctx->oformat;
for (i = 0; i < ifmt_ctx_array[0]->nb_streams; i++) {
//Create output AVStream according to input AVStream
AVStream *in_stream = ifmt_ctx_array[0]->streams[i];
AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
if (!out_stream) {
printf( "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
//Copy the settings of AVCodecContext
if (avcodec_copy_context(out_stream->codec, in_stream->codec) < 0) {
printf( "Failed to copy context from input to output stream codec context\n");
goto end;
}
out_stream->codec->codec_tag = 0;
if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
//Output information------------------
av_dump_format(ofmt_ctx, 0, out_filename, 1);
//Open output file
if (!(ofmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
if (ret < 0) {
printf( "Could not open output file '%s'", out_filename);
goto end;
}
}
//Write file header
if (avformat_write_header(ofmt_ctx, NULL) < 0) {
printf( "Error occurred when opening output file\n");
goto end;
}
AVFormatContext *input_ctx = ifmt_ctx_array[0];
//AVPacket pkt;
int pts_v = 0, pts_a = 0, dts_v = 0, dts_a = 0;
float vedioDuraTime = 0.0, audioDuraTime = 0.0;
int pts_v_temp = 0, pts_a_temp = 0, dts_v_temp = 0, dts_a_temp = 0;
int vedioIndex = 0;
while (1) {
AVStream *in_stream, *out_stream;
//Get an AVPacket
ret = av_read_frame(input_ctx, &pkt);
if (ret < 0) {
if (input_ctx != ifmt_ctx_array[input_array.count-1])
{

//calc the first media dura time
vedioDuraTime = ((float)input_ctx->streams[0]->time_base.num /
(float)input_ctx->streams[0]->time_base.den) * ((float)pts_v);
audioDuraTime = ((float)input_ctx->streams[1]->time_base.num /
(float)input_ctx->streams[1]->time_base.den) * ((float)pts_a);
printf("\nvedioDuraTime=%f\naudioDuraTime=%f\n",vedioDuraTime,audioDuraTime);
//                pts_v_temp += pts_v;
//                pts_v_temp+=1024;
//                dts_v_temp = pts_v_temp;
//                printf("\npts_v_temp=%d\npts_v_temp=%d\n",pts_v_temp,dts_v_temp);
//vedioDuraTime++;
//audioDuraTime++;
//calc the pts and dts end of the first media
if (audioDuraTime > vedioDuraTime)
{
dts_v = pts_v = audioDuraTime / ((float)input_ctx->streams[0]->time_base.num /
(float)input_ctx->streams[0]->time_base.den);
printf("\ndts_v=%d\npts_v=%d\n",dts_v,pts_v);
printf("\ndts_a=%d\npts_a=%d\n",dts_a,pts_a);
pts_v_temp+= pts_v;
//pts_v_temp+=512;
dts_v_temp = pts_v_temp;
pts_a_temp+=pts_a;
pts_a_temp+=1024;
dts_a_temp=pts_a_temp;
printf("\ndts_v=%d\npts_v=%d\n",dts_v,pts_v);
printf("\ndts_a=%d\npts_a=%d\n",dts_a,pts_a);
}
else
{
dts_a = pts_a = vedioDuraTime / ((float)input_ctx->streams[1]->time_base.num /
(float)input_ctx->streams[1]->time_base.den);
printf("\nnonononodts_a=%d\npts_a=%d\n",dts_a,pts_a);
pts_v_temp+= pts_v;
pts_v_temp+=1024;
dts_v_temp = pts_v_temp;
pts_a_temp+=pts_a;
pts_a_temp+=2048;
dts_a_temp=pts_a_temp;
printf("\nnonononodts_a=%d\npts_a=%d\n",dts_a,pts_a);
}
vedioIndex++;
input_ctx = ifmt_ctx_array[vedioIndex];
continue;
}
break;
}
in_stream  = input_ctx->streams[pkt.stream_index];
out_stream = ofmt_ctx->streams[pkt.stream_index];

if (pkt.stream_index == 0)
{printf("\npkt.pts=%lld\npkt.dts=%lld\n",pkt.pts,pkt.dts);
{
pts_v = pkt.pts;
dts_v = pkt.dts;
printf("\n============pts_v=%d\ndts_v=%d\n",pts_v,dts_v);
}
if (input_ctx != ifmt_ctx_array[0])
{
pkt.pts += pts_v_temp;
pkt.dts += dts_v_temp;
printf("\n============pts_v=%d\ndts_v=%d\n",pts_v,dts_v);
}
}
else if (pkt.stream_index == 1)
{
{
pts_a = pkt.pts;
dts_a = pkt.dts;
printf("\n============pts_a=%d\ndts_a=%d\n",pts_a,dts_a);
}
if (input_ctx != ifmt_ctx_array[0])
{
pkt.pts += pts_a_temp;
pkt.dts += dts_a_temp;
printf("\n============pts_a=%d\ndts_a=%d\n",pts_a,dts_a);
}
}

//        printf("\npkt.pts=%lld\npkt.dts=%lld\n",pkt.pts,pkt.dts);
//Convert PTS/DTS
pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
//pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
pkt.pos = -1;
//Write
if (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0) {
printf( "Error muxing packet\n");
//break;
}
printf("Write %8d frames to output file\n",frame_index);
av_free_packet(&pkt);
frame_index++;
}

//Write file trailer
av_write_trailer(ofmt_ctx);
end:
for (int i = 0; i<input_array.count; i++) {
avformat_close_input(&ifmt_ctx_array[i]);
}

/* close output */
if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
avio_close(ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);

}