爬虫9.C语言中使用FFmpeg将视频流与音频流合并为一个文件
C语言中使用FFmpeg将视频流与音频流合并为一个文件
编写代码
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typedef struct StreamContext {
AVCodecContext* dec_ctx;
AVCodecContext* enc_ctx;
AVStream* dec_stream;
AVStream* enc_stream;
} StreamContext;
static void log_packet(const AVFormatContext* fmt_ctx, const AVPacket* pkt, const char* tag) {
AVRational* time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
tag,
av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
pkt->stream_index);
}
int main(int argc, char** argv) {
if (argc != 4) {
fprintf(stderr, "Usage: %s <input_video> <input_audio> <output_file>\n", argv[0]);
return 1;
}
const char* video_file = argv[1];
const char* audio_file = argv[2];
const char* output_file = argv[3];
int ret = 0;
AVFormatContext* video_fmt_ctx = NULL;
AVFormatContext* audio_fmt_ctx = NULL;
AVFormatContext* output_fmt_ctx = NULL;
StreamContext* stream_ctx = NULL;
int video_stream_idx = -1;
int audio_stream_idx = -1;
int stream_count = 0;
// 打开输入文件
if ((ret = avformat_open_input(&video_fmt_ctx, video_file, NULL, NULL)) < 0) {
fprintf(stderr, "Could not open video input file '%s'\n", video_file);
goto end;
}
if ((ret = avformat_find_stream_info(video_fmt_ctx, NULL)) < 0) {
fprintf(stderr, "Failed to retrieve video input stream information\n");
goto end;
}
if ((ret = avformat_open_input(&audio_fmt_ctx, audio_file, NULL, NULL)) < 0) {
fprintf(stderr, "Could not open audio input file '%s'\n", audio_file);
goto end;
}
if ((ret = avformat_find_stream_info(audio_fmt_ctx, NULL)) < 0) {
fprintf(stderr, "Failed to retrieve audio input stream information\n");
goto end;
}
// 创建输出文件
avformat_alloc_output_context2(&output_fmt_ctx, NULL, NULL, output_file);
if (!output_fmt_ctx) {
fprintf(stderr, "Could not create output context\n");
ret = AVERROR_UNKNOWN;
goto end;
}
stream_count = video_fmt_ctx->nb_streams + audio_fmt_ctx->nb_streams;
stream_ctx = av_calloc(stream_count, sizeof(*stream_ctx));
if (!stream_ctx) {
ret = AVERROR(ENOMEM);
goto end;
}
// 处理视频流
for (unsigned int i = 0; i < video_fmt_ctx->nb_streams; i++) {
AVStream* in_stream = video_fmt_ctx->streams[i];
if (in_stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
video_stream_idx = i;
AVStream* out_stream = avformat_new_stream(output_fmt_ctx, NULL);
if (!out_stream) {
fprintf(stderr, "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
if (ret < 0) {
fprintf(stderr, "Failed to copy codec params\n");
goto end;
}
stream_ctx[i].dec_stream = in_stream;
stream_ctx[i].enc_stream = out_stream;
out_stream->codecpar->codec_tag = 0;
}
}
// 处理音频流
for (unsigned int i = 0; i < audio_fmt_ctx->nb_streams; i++) {
AVStream* in_stream = audio_fmt_ctx->streams[i];
if (in_stream->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
audio_stream_idx = i;
AVStream* out_stream = avformat_new_stream(output_fmt_ctx, NULL);
if (!out_stream) {
fprintf(stderr, "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
if (ret < 0) {
fprintf(stderr, "Failed to copy codec params\n");
goto end;
}
stream_ctx[video_fmt_ctx->nb_streams + i].dec_stream = in_stream;
stream_ctx[video_fmt_ctx->nb_streams + i].enc_stream = out_stream;
out_stream->codecpar->codec_tag = 0;
}
}
// 打开输出文件
if (!(output_fmt_ctx->oformat->flags & AVFMT_NOFILE)) {
ret = avio_open(&output_fmt_ctx->pb, output_file, AVIO_FLAG_WRITE);
if (ret < 0) {
fprintf(stderr, "Could not open output file '%s'\n", output_file);
goto end;
}
}
// 写入文件头
ret = avformat_write_header(output_fmt_ctx, NULL);
if (ret < 0) {
fprintf(stderr, "Error occurred when opening output file\n");
goto end;
}
// 读取视频包并写入
AVPacket* pkt = av_packet_alloc();
while (1) {
AVFormatContext* input_fmt_ctx;
int stream_idx;
int base_stream_idx;
if (av_read_frame(video_fmt_ctx, pkt) >= 0) {
input_fmt_ctx = video_fmt_ctx;
stream_idx = pkt->stream_index;
base_stream_idx = 0;
}
else if (av_read_frame(audio_fmt_ctx, pkt) >= 0) {
input_fmt_ctx = audio_fmt_ctx;
stream_idx = pkt->stream_index;
base_stream_idx = video_fmt_ctx->nb_streams;
}
else {
break;
}
StreamContext* stream = &stream_ctx[base_stream_idx + stream_idx];
// 转换时间基准
pkt->pts = av_rescale_q_rnd(pkt->pts,
stream->dec_stream->time_base,
stream->enc_stream->time_base,
AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
pkt->dts = av_rescale_q_rnd(pkt->dts,
stream->dec_stream->time_base,
stream->enc_stream->time_base,
AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX);
pkt->duration = av_rescale_q(pkt->duration,
stream->dec_stream->time_base,
stream->enc_stream->time_base);
pkt->stream_index = stream->enc_stream->index;
log_packet(output_fmt_ctx, pkt, "out");
ret = av_interleaved_write_frame(output_fmt_ctx, pkt);
if (ret < 0) {
fprintf(stderr, "Error muxing packet\n");
break;
}
av_packet_unref(pkt);
}
av_packet_free(&pkt);
// 写入文件尾
av_write_trailer(output_fmt_ctx);
end:
// 清理资源
if (video_fmt_ctx)
avformat_close_input(&video_fmt_ctx);
if (audio_fmt_ctx)
avformat_close_input(&audio_fmt_ctx);
if (output_fmt_ctx && !(output_fmt_ctx->oformat->flags & AVFMT_NOFILE))
avio_closep(&output_fmt_ctx->pb);
if (output_fmt_ctx)
avformat_free_context(output_fmt_ctx);
if (stream_ctx)
av_freep(&stream_ctx);
return ret ? 1 : 0;
}编译后运行
1
merge_av input_video.mp4 input_audio.mp3 output_av.mp4
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