版本：FFMpeg6.0
媒体信息打印
c
#include <libavformat/avformat.h>
#include <libavutil/log.h>
int main (int argc, char *argv[]) {
AVFormatContext *fmt_cxt = NULL;
int ret;
av_log_set_level(AV_LOG_INFO);
ret = avformat_open_input(&fmt_cxt, "/root/resource/1.mp4", NULL, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Can't open file: %s", av_err2str(ret));
return -1;
}
// 打印媒体信息
av_dump_format(fmt_cxt, 0, "/root/resource/1.mp4", 0);
avformat_close_input(&fmt_cxt);
return 0;
}提取音视频
音频和视频的区别在于av_find_best_stream时将AVMEDIA_TYPE_VIDEO改为AVMEDIA_TYPE_AUDIO
c
#include <libavformat/avformat.h>
#include <libavutil/log.h>
#include <libavutil/avutil.h>
int main (int argc, char *argv[]) {
// 1. 处理参数
char *src;
char *dst;
int ret;
int idx = -1;
AVFormatContext *pFmtCtx = NULL;
AVFormatContext *oFmtCtx = NULL;
const AVOutputFormat *outFmt = NULL;
AVStream *outStream = NULL;
AVStream *inStream = NULL;
AVPacket pkt;
av_log_set_level(AV_LOG_DEBUG);
if (argc < 3) {
av_log(NULL, AV_LOG_ERROR, "argument must be more than 3\n");
exit(-1);
}
src = argv[1];
dst = argv[2];
// 2. 打开多媒体文件
ret = avformat_open_input(&pFmtCtx, src, NULL, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "%s\n", av_err2str(ret));
exit(-1);
}
// 3. 从多媒体文件中找到音频流
idx = av_find_best_stream(pFmtCtx, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
if (idx < 0) {
av_log(pFmtCtx, AV_LOG_ERROR, "Does not include audio stream\n");
goto _ERROR;
}
// 4. 打开目的文件的上下文
oFmtCtx = avformat_alloc_context();
if (!oFmtCtx) {
av_log(pFmtCtx, AV_LOG_ERROR, "No memory\n");
goto _ERROR;
}
outFmt = av_guess_format(NULL, dst, NULL);
oFmtCtx->oformat = outFmt;
// 5. 为目的文件创建新的音频流
outStream = avformat_new_stream(oFmtCtx, NULL);
// 6. 设置输出视频参数
inStream = pFmtCtx->streams[idx];
avcodec_parameters_copy(outStream->codecpar, inStream->codecpar);
// 设置为0，会自动去找对应的编码器
outStream->codecpar->codec_tag = 0;
ret = avio_open2(&oFmtCtx->pb, dst, AVIO_FLAG_WRITE, NULL, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// 7. 写多媒体文件头到目的文件
ret = avformat_write_header(oFmtCtx, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// 8. 从源多媒体文件中读音频数据到目的文件中
while (av_read_frame(pFmtCtx, &pkt) >= 0) {
if (pkt.stream_index == idx) {
// 修改时间戳
pkt.pts = av_rescale_q_rnd(pkt.pts, inStream->time_base, outStream->time_base, (AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, inStream->time_base, outStream->time_base, (AV_ROUND_INF | AV_ROUND_PASS_MINMAX));
pkt.duration = av_rescale_q(pkt.duration, inStream->time_base, outStream->time_base);
pkt.stream_index = 0;
// 设置成-1，自己会去计算
pkt.pos = -1;
av_interleaved_write_frame(oFmtCtx, &pkt);
av_packet_unref(&pkt);
}
}
// 9. 写多媒体文件尾到目的文件
av_write_trailer(oFmtCtx);
// 10. 将申请的资源释放掉
_ERROR:
if (pFmtCtx) {
avformat_close_input(&pFmtCtx);
pFmtCtx = NULL;
}
if (oFmtCtx->pb) {
avio_close(oFmtCtx->pb);
}
if (oFmtCtx) {
avformat_free_context(oFmtCtx);
oFmtCtx = NULL;
}
return 0;
}转封装
c
#include <libavformat/avformat.h>
#include <libavutil/log.h>
#include <libavutil/avutil.h>
int main (int argc, char *argv[]) {
// 1. 处理参数
char *src;
char *dst;
int *stream_map = NULL;
int stream_idx = 0;
int ret;
int idx = -1;
int i = 0;
AVFormatContext *pFmtCtx = NULL;
AVFormatContext *oFmtCtx = NULL;
const AVOutputFormat *outFmt = NULL;
AVPacket pkt;
av_log_set_level(AV_LOG_DEBUG);
if (argc < 3) {
av_log(NULL, AV_LOG_ERROR, "argument must be more than 3\n");
exit(-1);
}
src = argv[1];
dst = argv[2];
// 2. 打开多媒体文件
ret = avformat_open_input(&pFmtCtx, src, NULL, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "%s\n", av_err2str(ret));
exit(-1);
}
// 3. 打开目的文件的上下文
avformat_alloc_output_context2(&oFmtCtx, NULL, NULL, dst);
if (!oFmtCtx) {
av_log(NULL, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
stream_map = av_calloc(pFmtCtx->nb_streams, sizeof(int));
if (!stream_map) {
av_log(NULL, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
for (i = 0; i < pFmtCtx->nb_streams; ++i) {
AVStream *outStream = NULL;
AVStream *inStream = pFmtCtx->streams[i];
AVCodecParameters *inCodecPar = inStream->codecpar;
if (inCodecPar->codec_type != AVMEDIA_TYPE_AUDIO &&
inCodecPar->codec_type != AVMEDIA_TYPE_VIDEO &&
inCodecPar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
stream_map[i] = -1;
continue;
}
stream_map[i] = stream_idx++;
// 4. 为目的文件创建新的音频流
outStream = avformat_new_stream(oFmtCtx, NULL);
if (!outStream) {
av_log(oFmtCtx, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
avcodec_parameters_copy(outStream->codecpar, inStream->codecpar);
// 设置为0，会自动去找对应的编码器
outStream->codecpar->codec_tag = 0;
}
ret = avio_open2(&oFmtCtx->pb, dst, AVIO_FLAG_WRITE, NULL, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// 5. 写多媒体文件头到目的文件
ret = avformat_write_header(oFmtCtx, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// 6. 从源多媒体文件中读音频数据到目的文件中
while (av_read_frame(pFmtCtx, &pkt) >= 0) {
AVStream *outStream = NULL;
AVStream *inStream = NULL;
if (stream_map[pkt.stream_index] < 0) {
av_packet_unref(&pkt);
continue;
}
inStream = pFmtCtx->streams[pkt.stream_index];
pkt.stream_index = stream_map[pkt.stream_index];
outStream = oFmtCtx->streams[pkt.stream_index];
av_packet_rescale_ts(&pkt, inStream->time_base, outStream->time_base);
// 设置成-1，自己会去计算
pkt.pos = -1;
av_interleaved_write_frame(oFmtCtx, &pkt);
av_packet_unref(&pkt);
}
// 7. 写多媒体文件尾到目的文件
av_write_trailer(oFmtCtx);
// 8. 将申请的资源释放掉
_ERROR:
if (pFmtCtx) {
avformat_close_input(&pFmtCtx);
pFmtCtx = NULL;
}
if (oFmtCtx->pb) {
avio_close(oFmtCtx->pb);
}
if (oFmtCtx) {
avformat_free_context(oFmtCtx);
oFmtCtx = NULL;
}
if (stream_map) {
av_free(stream_map);
}
return 0;
}剪辑
c
#include <libavformat/avformat.h>
#include <libavutil/log.h>
#include <libavutil/avutil.h>
#include <stdlib.h>
int main (int argc, char *argv[]) {
// 1. 处理参数
char *src;
char *dst;
int *stream_map = NULL;
int stream_idx = 0;
int ret;
int idx = -1;
int i = 0;
double startTime = 0;
double endTime = 0;
int64_t *dts_start_time = NULL;
int64_t *pts_start_time = NULL;
AVFormatContext *pFmtCtx = NULL;
AVFormatContext *oFmtCtx = NULL;
const AVOutputFormat *outFmt = NULL;
AVPacket pkt;
av_log_set_level(AV_LOG_DEBUG);
// cut src dst start end
if (argc < 5) {
av_log(NULL, AV_LOG_ERROR, "argument must be more than 5\n");
exit(-1);
}
src = argv[1];
dst = argv[2];
startTime = atof(argv[3]);
endTime = atof(argv[4]);
av_log(NULL, AV_LOG_INFO, "hello\n");
// 2. 打开多媒体文件
ret = avformat_open_input(&pFmtCtx, src, NULL, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "%s\n", av_err2str(ret));
exit(-1);
}
// 4. 打开目的文件的上下文
avformat_alloc_output_context2(&oFmtCtx, NULL, NULL, dst);
if (!oFmtCtx) {
av_log(NULL, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
stream_map = av_calloc(pFmtCtx->nb_streams, sizeof(int));
if (!stream_map) {
av_log(NULL, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
for (i = 0; i < pFmtCtx->nb_streams; ++i) {
AVStream *outStream = NULL;
AVStream *inStream = pFmtCtx->streams[i];
AVCodecParameters *inCodecPar = inStream->codecpar;
if (inCodecPar->codec_type != AVMEDIA_TYPE_AUDIO &&
inCodecPar->codec_type != AVMEDIA_TYPE_VIDEO &&
inCodecPar->codec_type != AVMEDIA_TYPE_SUBTITLE) {
stream_map[i] = -1;
continue;
}
stream_map[i] = stream_idx++;
// 5. 为目的文件创建新的音频流
outStream = avformat_new_stream(oFmtCtx, NULL);
if (!outStream) {
av_log(oFmtCtx, AV_LOG_ERROR, "NO MEMORY\n");
goto _ERROR;
}
avcodec_parameters_copy(outStream->codecpar, inStream->codecpar);
// 设置为0，会自动去找对应的编码器
outStream->codecpar->codec_tag = 0;
}
ret = avio_open2(&oFmtCtx->pb, dst, AVIO_FLAG_WRITE, NULL, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// 7. 写多媒体文件头到目的文件
ret = avformat_write_header(oFmtCtx, NULL);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
// seek
ret = av_seek_frame(pFmtCtx, -1, startTime * AV_TIME_BASE, AVSEEK_FLAG_BACKWARD);
if (ret < 0) {
av_log(oFmtCtx, AV_LOG_ERROR, "%s\n", av_err2str(ret));
goto _ERROR;
}
dts_start_time = av_calloc(pFmtCtx->nb_streams, sizeof(int64_t));
pts_start_time = av_calloc(pFmtCtx->nb_streams, sizeof(int64_t));
for (int t = 0; t < pFmtCtx->nb_streams; ++t) {
dts_start_time[t] = -1;
pts_start_time[t] = -1;
}
// 8. 从源多媒体文件中读音频数据到目的文件中
while (av_read_frame(pFmtCtx, &pkt) >= 0) {
AVStream *outStream = NULL;
AVStream *inStream = NULL;
if (dts_start_time[pkt.stream_index] == -1 && pkt.dts > 0) {
dts_start_time[pkt.stream_index] = pkt.dts;
}
if (pts_start_time[pkt.stream_index] == -1 && pkt.pts > 0) {
pts_start_time[pkt.stream_index] = pkt.pts;
}
if (stream_map[pkt.stream_index] < 0) {
av_packet_unref(&pkt);
continue;
}
pkt.pts = pkt.pts - pts_start_time[pkt.stream_index];
pkt.dts = pkt.dts - dts_start_time[pkt.stream_index];
if (pkt.dts > pkt.pts) {
pkt.pts = pkt.dts;
}
inStream = pFmtCtx->streams[pkt.stream_index];
if (av_q2d(inStream->time_base) * pkt.pts > endTime) {
av_log(oFmtCtx, AV_LOG_INFO, "success\n");
break;
}
pkt.stream_index = stream_map[pkt.stream_index];
outStream = oFmtCtx->streams[pkt.stream_index];
av_packet_rescale_ts(&pkt, inStream->time_base, outStream->time_base);
// 设置成-1，自己会去计算
pkt.pos = -1;
av_interleaved_write_frame(oFmtCtx, &pkt);
av_packet_unref(&pkt);
}
// 9. 写多媒体文件尾到目的文件
av_write_trailer(oFmtCtx);
// 10. 将申请的资源释放掉
_ERROR:
if (pFmtCtx) {
avformat_close_input(&pFmtCtx);
pFmtCtx = NULL;
}
if (oFmtCtx->pb) {
avio_close(oFmtCtx->pb);
}
if (oFmtCtx) {
avformat_free_context(oFmtCtx);
oFmtCtx = NULL;
}
if (stream_map) {
av_free(stream_map);
}
if (pts_start_time) {
av_free(pts_start_time);
}
if (dts_start_time) {
av_free(dts_start_time);
}
return 0;
}