在 iPhone 中使用 FFmpeg 合并两个或多个任意格式的视频文件

#import <ffmpeg/avformat.h>
#import <ffmpeg/avcodec.h>

NSString *inputFile1Path = @"path/to/input1.mp4";
NSString *inputFile2Path = @"path/to/input2.mp4";
NSString *outputFilePath = @"path/to/output.mp4";

av_register_all();

AVFormatContext *inputFormatContext1 = NULL;
AVFormatContext *inputFormatContext2 = NULL;
AVFormatContext *outputFormatContext = NULL;

if (avformat_open_input(&inputFormatContext1, [inputFile1Path UTF8String], NULL, NULL) != 0) {
    // 处理打开输入文件1失败的情况
}

if (avformat_open_input(&inputFormatContext2, [inputFile2Path UTF8String], NULL, NULL) != 0) {
    // 处理打开输入文件2失败的情况
}

if (avformat_alloc_output_context2(&outputFormatContext, NULL, NULL, [outputFilePath UTF8String]) < 0) {
    // 处理创建输出文件上下文失败的情况
}

AVStream *inputStream1 = inputFormatContext1->streams[0];
AVStream *inputStream2 = inputFormatContext2->streams[0];
AVStream *outputStream = avformat_new_stream(outputFormatContext, NULL);

if (avcodec_copy_context(outputStream->codec, inputStream1->codec) < 0) {
    // 处理复制输入流1的编解码器上下文失败的情况
}

outputStream->codec->codec_tag = 0;

if (avformat_write_header(outputFormatContext, NULL) < 0) {
    // 处理写入输出文件头部失败的情况
}

AVPacket packet;

while (av_read_frame(inputFormatContext1, &packet) >= 0) {
    packet.stream_index = outputStream->index;
    av_interleaved_write_frame(outputFormatContext, &packet);
    av_free_packet(&packet);
}

while (av_read_frame(inputFormatContext2, &packet) >= 0) {
    packet.stream_index = outputStream->index;
    av_interleaved_write_frame(outputFormatContext, &packet);
    av_free_packet(&packet);
}

av_write_trailer(outputFormatContext);

avformat_close_input(&inputFormatContext1);
avformat_close_input(&inputFormatContext2);

if (outputFormatContext && !(outputFormatContext->oformat->flags & AVFMT_NOFILE)) {
    avio_close(outputFormatContext->pb);
}

avformat_free_context(outputFormatContext);