一、環境介紹
PC機操作系統:Redhat 6.3 (32bit)
交叉編譯器: 4.5.1 (該編譯器是開發板光盤自帶的)
二、X264庫下載編譯安裝
2.1 下載X264庫
下載地址: https://www.videolan.org/developers/x264.html
2.2 解壓、配置X264庫
[wbyq@wbyq tiny4412]$ tar xvf /mnt/hgfs/linux-share-dir/x264-master.tar.bz2
[wbyq@wbyq tiny4412]$ cd x264-master/
[wbyq@wbyq x264-master]$ ./configure --prefix=$PWD/_install --disable-asm --enable-shared --enable-static --host=arm-none-linux-gnueabi
2.3 修改配置文件
打開當前目錄下的config.mak文件,將裏面的編譯器相關的命令加上arm-linux-前綴,因爲默認是使用gcc
[wbyq@wbyq x264-master]$ gedit config.mak
修改的地方如下圖所示:
2.4 編譯安裝X264
[wbyq@wbyq x264-master]$ make && make install
查看編譯安裝的文件:
[wbyq@wbyq x264-master]$ tree _install/
_install/
├── bin
│ └── x264
├── include
│ ├── x264_config.h
│ └── x264.h
└── lib
├── libx264.a
├── libx264.so -> libx264.so.160
├── libx264.so.160
└── pkgconfig
└── x264.pc
4 directories, 7 files
[wbyq@wbyq x264-master]$
三、FFMPEG庫下載編譯安裝
3.1 下載FFMPEG
下載地址: http://www.ffmpeg.org/download.html
3.2 編譯FFMPEG
[wbyq@wbyq ffmpeg-4.2.2]$ ./configure --enable-shared --enable-static --prefix=$PWD/_install --cross-prefix=arm-linux- --arch=arm --target-os=linux --enable-gpl --extra-cflags=-I/home/wbyq/work/tiny4412/x264-master/_install/include --extra-ldflags=-L/home/wbyq/work/tiny4412/x264-master/_install/lib --enable-ffmpeg --enable-libx264
[wbyq@wbyq ffmpeg-4.2.2]$ make && make install
3.3 查看編譯成功的文件
[wbyq@wbyq ffmpeg-4.2.2]$ tree _install/
_install/
├── bin
│ ├── ffmpeg
│ └── ffprobe
├── include
│ ├── libavcodec
│ │ ├── ac3_parser.h
│ │ ├── adts_parser.h
│ │ ├── avcodec.h
│ │ ├── avdct.h
│ │ ├── avfft.h
│ │ ├── d3d11va.h
│ │ ├── dirac.h
│ │ ├── dv_profile.h
│ │ ├── dxva2.h
│ │ ├── jni.h
│ │ ├── mediacodec.h
│ │ ├── qsv.h
│ │ ├── vaapi.h
│ │ ├── vdpau.h
│ │ ├── version.h
│ │ ├── videotoolbox.h
│ │ ├── vorbis_parser.h
│ │ └── xvmc.h
│ ├── libavdevice
│ │ ├── avdevice.h
│ │ └── version.h
│ ├── libavfilter
│ │ ├── avfilter.h
│ │ ├── buffersink.h
│ │ ├── buffersrc.h
│ │ └── version.h
│ ├── libavformat
│ │ ├── avformat.h
│ │ ├── avio.h
│ │ └── version.h
│ ├── libavutil
│ │ ├── adler32.h
│ │ ├── aes_ctr.h
│ │ ├── aes.h
│ │ ├── attributes.h
│ │ ├── audio_fifo.h
│ │ ├── avassert.h
│ │ ├── avconfig.h
│ │ ├── avstring.h
│ │ ├── avutil.h
│ │ ├── base64.h
│ │ ├── blowfish.h
│ │ ├── bprint.h
│ │ ├── bswap.h
│ │ ├── buffer.h
│ │ ├── camellia.h
│ │ ├── cast5.h
│ │ ├── channel_layout.h
│ │ ├── common.h
│ │ ├── cpu.h
│ │ ├── crc.h
│ │ ├── des.h
│ │ ├── dict.h
│ │ ├── display.h
│ │ ├── downmix_info.h
│ │ ├── encryption_info.h
│ │ ├── error.h
│ │ ├── eval.h
│ │ ├── ffversion.h
│ │ ├── fifo.h
│ │ ├── file.h
│ │ ├── frame.h
│ │ ├── hash.h
│ │ ├── hdr_dynamic_metadata.h
│ │ ├── hmac.h
│ │ ├── hwcontext_cuda.h
│ │ ├── hwcontext_d3d11va.h
│ │ ├── hwcontext_drm.h
│ │ ├── hwcontext_dxva2.h
│ │ ├── hwcontext.h
│ │ ├── hwcontext_mediacodec.h
│ │ ├── hwcontext_qsv.h
│ │ ├── hwcontext_vaapi.h
│ │ ├── hwcontext_vdpau.h
│ │ ├── hwcontext_videotoolbox.h
│ │ ├── imgutils.h
│ │ ├── intfloat.h
│ │ ├── intreadwrite.h
│ │ ├── lfg.h
│ │ ├── log.h
│ │ ├── lzo.h
│ │ ├── macros.h
│ │ ├── mastering_display_metadata.h
│ │ ├── mathematics.h
│ │ ├── md5.h
│ │ ├── mem.h
│ │ ├── motion_vector.h
│ │ ├── murmur3.h
│ │ ├── opt.h
│ │ ├── parseutils.h
│ │ ├── pixdesc.h
│ │ ├── pixelutils.h
│ │ ├── pixfmt.h
│ │ ├── random_seed.h
│ │ ├── rational.h
│ │ ├── rc4.h
│ │ ├── replaygain.h
│ │ ├── ripemd.h
│ │ ├── samplefmt.h
│ │ ├── sha512.h
│ │ ├── sha.h
│ │ ├── spherical.h
│ │ ├── stereo3d.h
│ │ ├── tea.h
│ │ ├── threadmessage.h
│ │ ├── timecode.h
│ │ ├── time.h
│ │ ├── timestamp.h
│ │ ├── tree.h
│ │ ├── twofish.h
│ │ ├── tx.h
│ │ ├── version.h
│ │ └── xtea.h
│ ├── libpostproc
│ │ ├── postprocess.h
│ │ └── version.h
│ ├── libswresample
│ │ ├── swresample.h
│ │ └── version.h
│ └── libswscale
│ ├── swscale.h
│ └── version.h
├── lib
│ ├── libavcodec.a
│ ├── libavcodec.so -> libavcodec.so.58.54.100
│ ├── libavcodec.so.58 -> libavcodec.so.58.54.100
│ ├── libavcodec.so.58.54.100
│ ├── libavdevice.a
│ ├── libavdevice.so -> libavdevice.so.58.8.100
│ ├── libavdevice.so.58 -> libavdevice.so.58.8.100
│ ├── libavdevice.so.58.8.100
│ ├── libavfilter.a
│ ├── libavfilter.so -> libavfilter.so.7.57.100
│ ├── libavfilter.so.7 -> libavfilter.so.7.57.100
│ ├── libavfilter.so.7.57.100
│ ├── libavformat.a
│ ├── libavformat.so -> libavformat.so.58.29.100
│ ├── libavformat.so.58 -> libavformat.so.58.29.100
│ ├── libavformat.so.58.29.100
│ ├── libavutil.a
│ ├── libavutil.so -> libavutil.so.56.31.100
│ ├── libavutil.so.56 -> libavutil.so.56.31.100
│ ├── libavutil.so.56.31.100
│ ├── libpostproc.a
│ ├── libpostproc.so -> libpostproc.so.55.5.100
│ ├── libpostproc.so.55 -> libpostproc.so.55.5.100
│ ├── libpostproc.so.55.5.100
│ ├── libswresample.a
│ ├── libswresample.so -> libswresample.so.3.5.100
│ ├── libswresample.so.3 -> libswresample.so.3.5.100
│ ├── libswresample.so.3.5.100
│ ├── libswscale.a
│ ├── libswscale.so -> libswscale.so.5.5.100
│ ├── libswscale.so.5 -> libswscale.so.5.5.100
│ ├── libswscale.so.5.5.100
│ └── pkgconfig
│ ├── libavcodec.pc
│ ├── libavdevice.pc
│ ├── libavfilter.pc
│ ├── libavformat.pc
│ ├── libavutil.pc
│ ├── libpostproc.pc
│ ├── libswresample.pc
│ └── libswscale.pc
└── share
├── ffmpeg
│ ├── examples
│ │ ├── avio_dir_cmd.c
│ │ ├── avio_reading.c
│ │ ├── decode_audio.c
│ │ ├── decode_video.c
│ │ ├── demuxing_decoding.c
│ │ ├── encode_audio.c
│ │ ├── encode_video.c
│ │ ├── extract_mvs.c
│ │ ├── filter_audio.c
│ │ ├── filtering_audio.c
│ │ ├── filtering_video.c
│ │ ├── http_multiclient.c
│ │ ├── hw_decode.c
│ │ ├── Makefile
│ │ ├── metadata.c
│ │ ├── muxing.c
│ │ ├── qsvdec.c
│ │ ├── README
│ │ ├── remuxing.c
│ │ ├── resampling_audio.c
│ │ ├── scaling_video.c
│ │ ├── transcode_aac.c
│ │ ├── transcoding.c
│ │ ├── vaapi_encode.c
│ │ └── vaapi_transcode.c
│ ├── ffprobe.xsd
│ ├── libvpx-1080p50_60.ffpreset
│ ├── libvpx-1080p.ffpreset
│ ├── libvpx-360p.ffpreset
│ ├── libvpx-720p50_60.ffpreset
│ └── libvpx-720p.ffpreset
└── man
├── man1
│ ├── ffmpeg.1
│ ├── ffmpeg-all.1
│ ├── ffmpeg-bitstream-filters.1
│ ├── ffmpeg-codecs.1
│ ├── ffmpeg-devices.1
│ ├── ffmpeg-filters.1
│ ├── ffmpeg-formats.1
│ ├── ffmpeg-protocols.1
│ ├── ffmpeg-resampler.1
│ ├── ffmpeg-scaler.1
│ ├── ffmpeg-utils.1
│ ├── ffprobe.1
│ └── ffprobe-all.1
└── man3
├── libavcodec.3
├── libavdevice.3
├── libavfilter.3
├── libavformat.3
├── libavutil.3
├── libswresample.3
└── libswscale.3
18 directories, 208 files
[wbyq@wbyq ffmpeg-4.2.2]$
四、部署編譯好的庫到目標開發板
4.1 拷貝庫到開發板
爲了方便部署到開發板,可以先創建一個“run_lib”目錄,然後將X264和FFMPEG編譯出來的動態庫拷貝到“run_lib”目錄下,再通過NFS服務器將“run_lib”目錄拷貝到目標開發板上。 將庫拷貝到開發板上之後,可以選擇直接把“run_lib”目錄下的庫拷貝到/lib目錄下,也可以將“”run_lib“”目錄的路徑添加到系統庫的環境變量裏。反正最終目的,只要讓程序在運行時,能找到使用的庫就對了。
拷貝過程如下:
[wbyq@wbyq tiny4412]$ ls
ffmpeg-4.2.2 x264-master
[wbyq@wbyq tiny4412]$ mkdir run_lib
[wbyq@wbyq tiny4412]$ cd run_lib/
[wbyq@wbyq run_lib]$ cp ../ffmpeg-4.2.2/_install/lib/*.so* ./
[wbyq@wbyq run_lib]$ cp ../x264-master/_install/lib/*.so* ./
[wbyq@wbyq run_lib]$ ls
libavcodec.so libavfilter.so libavutil.so libswresample.so libx264.so
libavcodec.so.58 libavfilter.so.7 libavutil.so.56 libswresample.so.3 libx264.so.160
libavcodec.so.58.54.100 libavfilter.so.7.57.100 libavutil.so.56.31.100 libswresample.so.3.5.100
libavdevice.so libavformat.so libpostproc.so libswscale.so
libavdevice.so.58 libavformat.so.58 libpostproc.so.55 libswscale.so.5
libavdevice.so.58.8.100 libavformat.so.58.29.100 libpostproc.so.55.5.100 libswscale.so.5.5.100
4.2 拷貝可執行命令到開發板進行測試
將庫拷貝到開發板之後,再將“ffmpeg-4.2.2/_install/bin/ffmpeg” 可執行文件拷貝到開發板的bin目錄下。
下面是在開發板的終端運行ffmpeg命令效果:
[root@tiny4412 ]# ls
bin etc linuxrc nfs.sh root tmp work
code home lost+found opt sbin usr
dev lib mnt proc sys var
[root@tiny4412 ]# ffmpeg
ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 4.5.1 (ctng-1.8.1-FA)
configuration: --enable-shared --enable-static --prefix=/home/wbyq/work/tiny4412/ffmpeg-4.2.2/_install --cross-prefix=arm-linux- --arch=arm --target-os=linux --enable-gpl --extra-cflags=-I/home/wbyq/work/tiny4412/x264-master/_install/include --extra-ldflags=-L/home/wbyq/work/tiny4412/x264-master/_install/lib --enable-ffmpeg --enable-libx264
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...
Use -h to get full help or, even better, run 'man ffmpeg'
[root@tiny4412 ]#
命令能運行,接來下就可以進行音頻視頻相關的程序開發了。
五、測試FFMPEG庫:使用ffmpeg採集攝像頭數據編碼爲MP4保存到本地
5.1 完整代碼
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <libavutil/avassert.h>
#include <libavutil/channel_layout.h>
#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libswresample/swresample.h>
#define STREAM_DURATION 50.0 /*錄製視頻的持續時間 秒*/
#define STREAM_FRAME_RATE 5 /* images/s 這裏可以根據攝像頭的採集速度來設置幀率 */
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
#define SCALE_FLAGS SWS_BICUBIC
//存放視頻的寬度和高度
int video_width;
int video_height;
// 單個輸出AVStream的包裝器
typedef struct OutputStream
{
AVStream *st;
AVCodecContext *enc;
/*下一幀的點數*/
int64_t next_pts;
int samples_count;
AVFrame *frame;
AVFrame *tmp_frame;
float t, tincr, tincr2;
struct SwsContext *sws_ctx;
struct SwrContext *swr_ctx;
}OutputStream;
typedef struct IntputDev
{
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFormatContext *v_ifmtCtx;
int videoindex;
struct SwsContext *img_convert_ctx;
AVPacket *in_packet;
AVFrame *pFrame,*pFrameYUV;
}IntputDev;
static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt)
{
AVRational *time_base = &fmt_ctx->streams[pkt->stream_index]->time_base;
printf("pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
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);
}
static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
{
/* 將輸出數據包時間戳值從編解碼器重新調整爲流時基 */
av_packet_rescale_ts(pkt, *time_base, st->time_base);
pkt->stream_index = st->index;
/*將壓縮的幀寫入媒體文件。*/
log_packet(fmt_ctx, pkt);
return av_interleaved_write_frame(fmt_ctx, pkt);
}
/*添加輸出流。 */
static void add_stream(OutputStream *ost, AVFormatContext *oc,AVCodec **codec,enum AVCodecID codec_id)
{
AVCodecContext *c;
int i;
/* find the encoder */
*codec = avcodec_find_encoder(codec_id);
if (!(*codec))
{
fprintf(stderr, "Could not find encoder for '%s'\n",
avcodec_get_name(codec_id));
exit(1);
}
ost->st = avformat_new_stream(oc, NULL);
if (!ost->st) {
fprintf(stderr, "Could not allocate stream\n");
exit(1);
}
ost->st->id = oc->nb_streams-1;
c = avcodec_alloc_context3(*codec);
if (!c) {
fprintf(stderr, "Could not alloc an encoding context\n");
exit(1);
}
ost->enc = c;
switch((*codec)->type)
{
case AVMEDIA_TYPE_AUDIO:
c->sample_fmt = (*codec)->sample_fmts ?
(*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
c->bit_rate = 64000;
c->sample_rate = 44100;
if ((*codec)->supported_samplerates) {
c->sample_rate = (*codec)->supported_samplerates[0];
for (i = 0; (*codec)->supported_samplerates[i]; i++) {
if ((*codec)->supported_samplerates[i] == 44100)
c->sample_rate = 44100;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
c->channel_layout = AV_CH_LAYOUT_STEREO;
if ((*codec)->channel_layouts) {
c->channel_layout = (*codec)->channel_layouts[0];
for (i = 0; (*codec)->channel_layouts[i]; i++) {
if ((*codec)->channel_layouts[i] == AV_CH_LAYOUT_STEREO)
c->channel_layout = AV_CH_LAYOUT_STEREO;
}
}
c->channels = av_get_channel_layout_nb_channels(c->channel_layout);
ost->st->time_base = (AVRational){ 1, c->sample_rate };
break;
case AVMEDIA_TYPE_VIDEO:
c->codec_id = codec_id;
c->bit_rate = 2500000; //平均比特率,例子代碼默認值是400000
/* 分辨率必須是2的倍數。*/
c->width=video_width;
c->height=video_height;
/*時基:這是基本的時間單位(以秒爲單位)
*表示其中的幀時間戳。 對於固定fps內容,
*時基應爲1 /framerate,時間戳增量應爲
*等於1。*/
ost->st->time_base = (AVRational){1,STREAM_FRAME_RATE}; //幀率設置
c->time_base = ost->st->time_base;
c->gop_size = 12; /* 最多每十二幀發射一幀內幀 */
c->pix_fmt = STREAM_PIX_FMT;
if(c->codec_id == AV_CODEC_ID_MPEG2VIDEO)
{
/* 只是爲了測試,我們還添加了B幀 */
c->max_b_frames = 2;
}
if(c->codec_id == AV_CODEC_ID_MPEG1VIDEO)
{
/*需要避免使用其中一些係數溢出的宏塊。
*普通視頻不會發生這種情況,因爲
*色度平面的運動與亮度平面不匹配。 */
c->mb_decision = 2;
}
break;
default:
break;
}
/* 某些格式希望流頭分開。 */
if (oc->oformat->flags & AVFMT_GLOBALHEADER)
c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}
static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
AVFrame *picture;
int ret;
picture = av_frame_alloc();
if (!picture)
return NULL;
picture->format = pix_fmt;
picture->width = width;
picture->height = height;
/* 爲幀數據分配緩衝區 */
ret = av_frame_get_buffer(picture, 32);
if(ret<0)
{
fprintf(stderr, "Could not allocate frame data.\n");
exit(1);
}
return picture;
}
static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
int ret;
AVCodecContext *c = ost->enc;
AVDictionary *opt = NULL;
av_dict_copy(&opt, opt_arg, 0);
/* open the codec */
ret = avcodec_open2(c, codec, &opt);
av_dict_free(&opt);
if (ret < 0)
{
fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
exit(1);
}
/* 分配並初始化可重用框架 */
ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
if (!ost->frame)
{
fprintf(stderr, "Could not allocate video frame\n");
exit(1);
}
printf("ost->frame alloc success fmt=%d w=%d h=%d\n",c->pix_fmt,c->width, c->height);
/*如果輸出格式不是YUV420P,則爲臨時YUV420P
*也需要圖片。 然後將其轉換爲所需的
*輸出格式。 */
ost->tmp_frame = NULL;
if(c->pix_fmt != AV_PIX_FMT_YUV420P)
{
ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
if (!ost->tmp_frame)
{
fprintf(stderr, "Could not allocate temporary picture\n");
exit(1);
}
}
/* 將流參數複製到多路複用器*/
ret=avcodec_parameters_from_context(ost->st->codecpar, c);
if(ret<0)
{
fprintf(stderr, "Could not copy the stream parameters\n");
exit(1);
}
}
/*
*編碼一個視頻幀
*編碼完成後返回1,否則返回0
*/
static int write_video_frame(AVFormatContext *oc, OutputStream *ost,AVFrame *frame)
{
int ret;
AVCodecContext *c;
int got_packet=0;
AVPacket pkt={0};
if(frame==NULL)
return 1;
c = ost->enc;
av_init_packet(&pkt);
/* 編碼圖像*/
ret = avcodec_encode_video2(c, &pkt, frame, &got_packet);
if(ret<0)
{
fprintf(stderr, "Error encoding video frame: %s\n", av_err2str(ret));
exit(1);
}
printf("--------------video- pkt.pts=%s\n",av_ts2str(pkt.pts));
printf("----st.num=%d st.den=%d codec.num=%d codec.den=%d---------\n",ost->st->time_base.num,ost->st->time_base.den,
c->time_base.num,c->time_base.den);
if(got_packet)
{
ret = write_frame(oc, &c->time_base, ost->st, &pkt);
}else
{
ret = 0;
}
if(ret<0)
{
fprintf(stderr, "Error while writing video frame: %s\n", av_err2str(ret));
exit(1);
}
return (frame || got_packet) ? 0 : 1;
}
static AVFrame *get_video_frame(OutputStream *ost,IntputDev* input,int *got_pic)
{
int ret, got_picture;
AVCodecContext *c = ost->enc;
AVFrame * ret_frame=NULL;
if(av_compare_ts(ost->next_pts, c->time_base,STREAM_DURATION, (AVRational){1,1})>=0)
return NULL;
/*當我們將幀傳遞給編碼器時,它可能會保留對它的引用
*內部,確保我們在這裏不覆蓋它*/
if (av_frame_make_writable(ost->frame)<0)
exit(1);
if(av_read_frame(input->v_ifmtCtx, input->in_packet)>=0)
{
if(input->in_packet->stream_index==input->videoindex)
{
ret = avcodec_decode_video2(input->pCodecCtx, input->pFrame, &got_picture, input->in_packet);
*got_pic=got_picture;
if(ret<0)
{
printf("Decode Error.\n");
av_packet_unref(input->in_packet);
return NULL;
}
if(got_picture)
{
sws_scale(input->img_convert_ctx, (const unsigned char* const*)input->pFrame->data, input->pFrame->linesize, 0, input->pCodecCtx->height, ost->frame->data, ost->frame->linesize);
ost->frame->pts =ost->next_pts++;
ret_frame= ost->frame;
}
}
av_packet_unref(input->in_packet);
}
return ret_frame;
}
static void close_stream(AVFormatContext *oc, OutputStream *ost)
{
avcodec_free_context(&ost->enc);
av_frame_free(&ost->frame);
av_frame_free(&ost->tmp_frame);
sws_freeContext(ost->sws_ctx);
swr_free(&ost->swr_ctx);
}
/*
採集攝像頭數據編碼成MP4視頻
*/
int main(int argc, char **argv)
{
OutputStream video_st = { 0 }, audio_st = { 0 };
const char *filename;
AVOutputFormat *fmt;
AVFormatContext *oc;
AVCodec *audio_codec, *video_codec;
int ret;
int have_video = 0, have_audio = 0;
int encode_video = 0, encode_audio = 0;
AVDictionary *opt = NULL;
int i;
if(argc<3)
{
//./app /dev/video0 123.mp4
printf("用法: %s <攝像頭設備節點> <文件名稱> \n", argv[0]);
return 1;
}
filename = argv[2];
printf("當前存儲的視頻文件名稱:%s\n",filename);
/*分配輸出媒體環境*/
avformat_alloc_output_context2(&oc, NULL, NULL, filename);
if(!oc)
{
printf("無法從文件擴展名推斷出輸出格式:使用MPEG。\n");
avformat_alloc_output_context2(&oc, NULL, "mpeg", filename);
}
if(!oc)return 1;
//添加攝像頭----------------------------------
IntputDev video_input={0};
AVCodecContext *pCodecCtx;
AVCodec *pCodec;
AVFormatContext *v_ifmtCtx;
avdevice_register_all();
v_ifmtCtx = avformat_alloc_context();
//Linux下指定攝像頭信息
AVInputFormat *ifmt=av_find_input_format("video4linux2");
if(avformat_open_input(&v_ifmtCtx,argv[1],ifmt,NULL)!=0)
{
printf("無法打開輸入流.%s\n",argv[1]);
return -1;
}
if(avformat_find_stream_info(v_ifmtCtx,NULL)<0)
{
printf("找不到流信息.\n");
return -1;
}
int videoindex=-1;
for(i=0; i<v_ifmtCtx->nb_streams; i++)
if(v_ifmtCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO)
{
videoindex=i;
printf("videoindex=%d\n",videoindex);
break;
}
if(videoindex==-1)
{
printf("找不到視頻流。\n");
return -1;
}
pCodecCtx=v_ifmtCtx->streams[videoindex]->codec;
pCodec=avcodec_find_decoder(pCodecCtx->codec_id);
if(pCodec==NULL)
{
printf("找不到編解碼器。\n");
return -1;
}
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)
{
printf("無法打開編解碼器。\n");
return -1;
}
AVFrame *pFrame,*pFrameYUV;
pFrame=av_frame_alloc();
pFrameYUV=av_frame_alloc();
unsigned char *out_buffer=(unsigned char *)av_malloc(av_image_get_buffer_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height,16));
av_image_fill_arrays((AVPicture *)pFrameYUV->data,(AVPicture *)pFrameYUV->linesize, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height,16);
printf("攝像頭尺寸(WxH): %d x %d \n",pCodecCtx->width, pCodecCtx->height);
video_width=pCodecCtx->width;
video_height=pCodecCtx->height;
struct SwsContext *img_convert_ctx;
img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
AVPacket *in_packet=(AVPacket *)av_malloc(sizeof(AVPacket));
video_input.img_convert_ctx=img_convert_ctx;
video_input.in_packet=in_packet;
video_input.pCodecCtx=pCodecCtx;
video_input.pCodec=pCodec;
video_input.v_ifmtCtx=v_ifmtCtx;
video_input.videoindex=videoindex;
video_input.pFrame=pFrame;
video_input.pFrameYUV=pFrameYUV;
//-----------------------------添加攝像頭結束
fmt=oc->oformat;
/*使用默認格式的編解碼器添加音頻和視頻流並初始化編解碼器。*/
printf("fmt->video_codec = %d\n", fmt->video_codec);
if(fmt->video_codec != AV_CODEC_ID_NONE)
{
add_stream(&video_st,oc,&video_codec,fmt->video_codec);
have_video=1;
encode_video=1;
}
/*現在已經設置了所有參數,可以打開音頻並視頻編解碼器,並分配必要的編碼緩衝區。*/
if(have_video)open_video(oc, video_codec, &video_st, opt);
av_dump_format(oc,0,filename,1);
/* 打開輸出文件(如果需要) */
if(!(fmt->flags & AVFMT_NOFILE))
{
ret=avio_open(&oc->pb,filename,AVIO_FLAG_WRITE);
if(ret<0)
{
fprintf(stderr, "打不開'%s': %s\n", filename,av_err2str(ret));
return 1;
}
}
/* 編寫流頭(如果有)*/
ret=avformat_write_header(oc, &opt);
if(ret<0)
{
fprintf(stderr, "打開輸出文件時發生錯誤: %s\n",av_err2str(ret));
return 1;
}
int got_pic;
while(encode_video)
{
/*選擇要編碼的流*/
AVFrame *frame=get_video_frame(&video_st,&video_input,&got_pic);
if(!got_pic)
{
usleep(10000);
continue;
}
encode_video=!write_video_frame(oc,&video_st,frame);
}
av_write_trailer(oc);
sws_freeContext(video_input.img_convert_ctx);
avcodec_close(video_input.pCodecCtx);
av_free(video_input.pFrameYUV);
av_free(video_input.pFrame);
avformat_close_input(&video_input.v_ifmtCtx);
/*關閉每個編解碼器*/
if (have_video)close_stream(oc, &video_st);
/*關閉輸出文件*/
if (!(fmt->flags & AVFMT_NOFILE))avio_closep(&oc->pb);
/*釋放流*/
avformat_free_context(oc);
return 0;
}
5.2 Makefile文件
app1:
arm-linux-gcc ffmpeg_video.c -I /home/wbyq/work/tiny4412/ffmpeg-4.2.2/_install/include -L /home/wbyq/work/tiny4412/ffmpeg-4.2.2/_install/lib -I/home/wbyq/work/tiny4412/x264-master/_install/include -L/home/wbyq/work/tiny4412/x264-master/_install/lib -lavcodec -lavfilter -lavutil -lswresample -lavdevice -lavformat -lpostproc -lswscale -lx264
5.3 運行測試
[root@tiny4412 code]# ./a.out /dev/video15 123.mp4
由於目前開發板上沒有安裝播放器,下面是將123.MP4文件拷貝到PC機上播放的效果。
下面公衆號有全套的C/C++/QT的基礎教程,歡迎關注: