我已经开始学习如何使用 ffmpeg，它对所有教程和可用示例(如 this)进行了严重的弃用。 .
我正在寻找创建输出视频的代码。
不幸的是，大部分good examples专注于从文件中读取而不是创建文件。
Here ，我发现了一个弃用的例子，我花了很长时间来修复它的错误，直到它变成了这样:
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string>
extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libswscale/swscale.h>
#include <libavformat/avio.h>
#include <libavutil/opt.h>
}
#define WIDTH 800
#define HEIGHT 480
#define STREAM_NB_FRAMES ((int)(STREAM_DURATION * FRAME_RATE))
#define FRAME_RATE 24
#define PIXEL_FORMAT AV_PIX_FMT_YUV420P
#define STREAM_DURATION 5.0 //seconds
#define BIT_RATE 400000
#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
#define CODEC_FLAG_GLOBAL_HEADER AV_CODEC_FLAG_GLOBAL_HEADER
#define AVFMT_RAWPICTURE 0x0020
using namespace std;
static int sws_flags = SWS_BICUBIC;
AVFrame *picture, *tmp_picture;
uint8_t *video_outbuf;
int frame_count, video_outbuf_size;
/****** IF LINUX ******/
inline int sprintf_s(char* buffer, size_t sizeOfBuffer, const char* format, ...)
{
va_list ap;
va_start(ap, format);
int result = vsnprintf(buffer, sizeOfBuffer, format, ap);
va_end(ap);
return result;
}
/****** IF LINUX ******/
template<size_t sizeOfBuffer>
inline int sprintf_s(char (&buffer)[sizeOfBuffer], const char* format, ...)
{
va_list ap;
va_start(ap, format);
int result = vsnprintf(buffer, sizeOfBuffer, format, ap);
va_end(ap);
return result;
}
static void closeVideo(AVFormatContext *oc, AVStream *st)
{
avcodec_close(st->codec);
av_free(picture->data[0]);
av_free(picture);
if (tmp_picture)
{
av_free(tmp_picture->data[0]);
av_free(tmp_picture);
}
av_free(video_outbuf);
}
static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
AVFrame *picture;
uint8_t *picture_buf;
int size;
picture = av_frame_alloc();
if(!picture)
return NULL;
size = avpicture_get_size(pix_fmt, width, height);
picture_buf = (uint8_t*)(av_malloc(size));
if (!picture_buf)
{
av_free(picture);
return NULL;
}
avpicture_fill((AVPicture *) picture, picture_buf, pix_fmt, WIDTH, HEIGHT);
return picture;
}
static void openVideo(AVFormatContext *oc, AVStream *st)
{
AVCodec *codec;
AVCodecContext *c;
c = st->codec;
if(c->idct_algo == AV_CODEC_ID_H264)
av_opt_set(c->priv_data, "preset", "slow", 0);
codec = avcodec_find_encoder(c->codec_id);
if(!codec)
{
std::cout << "Codec not found." << std::endl;
std::cin.get();std::cin.get();exit(1);
}
if(codec->id == AV_CODEC_ID_H264)
av_opt_set(c->priv_data, "preset", "medium", 0);
if(avcodec_open2(c, codec, NULL) < 0)
{
std::cout << "Could not open codec." << std::endl;
std::cin.get();std::cin.get();exit(1);
}
video_outbuf = NULL;
if(!(oc->oformat->flags & AVFMT_RAWPICTURE))
{
video_outbuf_size = 200000;
video_outbuf = (uint8_t*)(av_malloc(video_outbuf_size));
}
picture = alloc_picture(c->pix_fmt, c->width, c->height);
if(!picture)
{
std::cout << "Could not allocate picture" << std::endl;
std::cin.get();exit(1);
}
tmp_picture = NULL;
if(c->pix_fmt != AV_PIX_FMT_YUV420P)
{
tmp_picture = alloc_picture(AV_PIX_FMT_YUV420P, WIDTH, HEIGHT);
if(!tmp_picture)
{
std::cout << " Could not allocate temporary picture" << std::endl;
std::cin.get();exit(1);
}
}
}
static AVStream* addVideoStream(AVFormatContext *context, enum AVCodecID codecID)
{
AVCodecContext *codec;
AVStream *stream;
stream = avformat_new_stream(context, NULL);
if(!stream)
{
std::cout << "Could not alloc stream." << std::endl;
std::cin.get();exit(1);
}
codec = stream->codec;
codec->codec_id = codecID;
codec->codec_type = AVMEDIA_TYPE_VIDEO;
// sample rate
codec->bit_rate = BIT_RATE;
// resolution must be a multiple of two
codec->width = WIDTH;
codec->height = HEIGHT;
codec->time_base.den = FRAME_RATE; // stream fps
codec->time_base.num = 1;
codec->gop_size = 12; // intra frame every twelve frames at most
codec->pix_fmt = PIXEL_FORMAT;
if(codec->codec_id == AV_CODEC_ID_MPEG2VIDEO)
codec->max_b_frames = 2; // for testing, B frames
if(codec->codec_id == AV_CODEC_ID_MPEG1VIDEO)
codec->mb_decision = 2;
if(context->oformat->flags & AVFMT_GLOBALHEADER)
codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
return stream;
}
static void fill_yuv_image(AVFrame *pict, int frame_index, int width, int height)
{
int x, y, i;
i = frame_index;
/* Y */
for(y=0;y<height;y++) {
for(x=0;x<width;x++) {
pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
}
}
/* Cb and Cr */
for(y=0;y<height/2;y++) {
for(x=0;x<width/2;x++) {
pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5;
}
}
}
static void write_video_frame(AVFormatContext *oc, AVStream *st)
{
int out_size, ret;
AVCodecContext *c;
static struct SwsContext *img_convert_ctx;
c = st->codec;
if(frame_count >= STREAM_NB_FRAMES)
{
}
else
{
if(c->pix_fmt != AV_PIX_FMT_YUV420P)
{
if(img_convert_ctx = NULL)
{
img_convert_ctx = sws_getContext(WIDTH, HEIGHT, AV_PIX_FMT_YUV420P, WIDTH, HEIGHT,
c->pix_fmt, sws_flags, NULL, NULL, NULL);
if(img_convert_ctx == NULL)
{
std::cout << "Cannot initialize the conversion context" << std::endl;
std::cin.get();exit(1);
}
}
fill_yuv_image(tmp_picture, frame_count, WIDTH, HEIGHT);
sws_scale(img_convert_ctx, tmp_picture->data, tmp_picture->linesize, 0, HEIGHT,
picture->data, picture->linesize);
}
else
{
fill_yuv_image(picture, frame_count, WIDTH, HEIGHT);
}
}
if (oc->oformat->flags & AVFMT_RAWPICTURE)
{
/* raw video case. The API will change slightly in the near
futur for that */
AVPacket pkt;
av_init_packet(&pkt);
pkt.flags |= AV_PKT_FLAG_KEY;
pkt.stream_index= st->index;
pkt.data= (uint8_t *)picture;
pkt.size= sizeof(AVPicture);
ret = av_interleaved_write_frame(oc, &pkt);
}
else
{
/* encode the image */
out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
/* if zero size, it means the image was buffered */
if (out_size > 0)
{
AVPacket pkt;
av_init_packet(&pkt);
if (c->coded_frame->pts != AV_NOPTS_VALUE)
pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
if(c->coded_frame->key_frame)
pkt.flags |= AV_PKT_FLAG_KEY;
pkt.stream_index= st->index;
pkt.data= video_outbuf;
pkt.size= out_size;
/* write the compressed frame in the media file */
ret = av_interleaved_write_frame(oc, &pkt);
} else {
ret = 0;
}
}
if (ret != 0) {
std::cout << "Error while writing video frames" << std::endl;
std::cin.get();exit(1);
}
frame_count++;
}
int main ( int argc, char *argv[] )
{
const char* filename = "test.h264";
AVOutputFormat *outputFormat;
AVFormatContext *context;
AVCodecContext *codec;
AVStream *videoStream;
double videoPTS;
// init libavcodec, register all codecs and formats
av_register_all();
// auto detect the output format from the name
outputFormat = av_guess_format(NULL, filename, NULL);
if(!outputFormat)
{
std::cout << "Cannot guess output format! Using mpeg!" << std::endl;
std::cin.get();
outputFormat = av_guess_format(NULL, "h263" , NULL);
}
if(!outputFormat)
{
std::cout << "Could not find suitable output format." << std::endl;
std::cin.get();exit(1);
}
context = avformat_alloc_context();
if(!context)
{
std::cout << "Cannot allocate avformat memory." << std::endl;
std::cin.get();exit(1);
}
context->oformat = outputFormat;
sprintf_s(context->filename, sizeof(context->filename), "%s", filename);
std::cout << "Is '" << context->filename << "' = '" << filename << "'" << std::endl;
videoStream = NULL;
outputFormat->audio_codec = AV_CODEC_ID_NONE;
videoStream = addVideoStream(context, outputFormat->video_codec);
/* still needed?
if(av_set_parameters(context, NULL) < 0)
{
std::cout << "Invalid output format parameters." << std::endl;
exit(0);
}*/
av_dump_format(context, 0, filename, 1);
if(videoStream)
openVideo(context, videoStream);
if(!outputFormat->flags & AVFMT_NOFILE)
{
if(avio_open(&context->pb, filename, AVIO_FLAG_READ_WRITE) < 0)
{
std::cout << "Could not open " << filename << std::endl;
std::cin.get();exit(1);
}
}
avformat_write_header(context, 0);
while(true)
{
if(videoStream)
videoPTS = (double) videoStream->pts.val * videoStream->time_base.num / videoStream->time_base.den;
else
videoPTS = 0.;
if((!videoStream || videoPTS >= STREAM_DURATION))
{
break;
}
write_video_frame(context, videoStream);
}
av_write_trailer(context);
if(videoStream)
closeVideo(context, videoStream);
for(int i = 0; i < context->nb_streams; i++)
{
av_freep(&context->streams[i]->codec);
av_freep(&context->streams[i]);
}
if(!(outputFormat->flags & AVFMT_NOFILE))
{
avio_close(context->pb);
}
av_free(context);
std::cin.get();
return 0;
}
编译:
g++ -I ./FFmpeg/ video.cpp -L fflibs -lavcodec -lavformat
代码有两个错误:
video.cpp:249:84: error: ‘avcodec_encode_video’ was not declared in this scope
out_size = avcodec_encode_video(c, video_outbuf, video_outbuf_size, picture);
^
video.cpp: In function ‘int main(int, char**)’:
video.cpp:342:46: error: ‘AVStream {aka struct AVStream}’ has no member named ‘pts’
videoPTS = (double) videoStream->pts.val * videoStream->time_base.num / videoStream->time_base.den;
^
以及大量弃用警告。
video.cpp: In function ‘void closeVideo(AVFormatContext*, AVStream*)’:
video.cpp:60:23: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
avcodec_close(st->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:60:23: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
avcodec_close(st->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:60:23: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
avcodec_close(st->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp: In function ‘AVFrame* alloc_picture(AVPixelFormat, int, int)’:
video.cpp:80:12: warning: ‘int avpicture_get_size(AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
size = avpicture_get_size(pix_fmt, width, height);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5228:5: note: declared here
int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);
^
video.cpp:80:12: warning: ‘int avpicture_get_size(AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
size = avpicture_get_size(pix_fmt, width, height);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5228:5: note: declared here
int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);
^
video.cpp:80:53: warning: ‘int avpicture_get_size(AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
size = avpicture_get_size(pix_fmt, width, height);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5228:5: note: declared here
int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);
^
video.cpp:87:5: warning: ‘int avpicture_fill(AVPicture*, const uint8_t*, AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
avpicture_fill((AVPicture *) picture, picture_buf, pix_fmt, WIDTH, HEIGHT);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5213:5: note: declared here
int avpicture_fill(AVPicture *picture, const uint8_t *ptr,
^
video.cpp:87:5: warning: ‘int avpicture_fill(AVPicture*, const uint8_t*, AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
avpicture_fill((AVPicture *) picture, picture_buf, pix_fmt, WIDTH, HEIGHT);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5213:5: note: declared here
int avpicture_fill(AVPicture *picture, const uint8_t *ptr,
^
video.cpp:87:78: warning: ‘int avpicture_fill(AVPicture*, const uint8_t*, AVPixelFormat, int, int)’ is deprecated [-Wdeprecated-declarations]
avpicture_fill((AVPicture *) picture, picture_buf, pix_fmt, WIDTH, HEIGHT);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:5213:5: note: declared here
int avpicture_fill(AVPicture *picture, const uint8_t *ptr,
^
video.cpp: In function ‘void openVideo(AVFormatContext*, AVStream*)’:
video.cpp:96:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:96:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:96:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp: In function ‘AVStream* addVideoStream(AVFormatContext*, AVCodecID)’:
video.cpp:151:21: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
codec = stream->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:151:21: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
codec = stream->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:151:21: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
codec = stream->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp: In function ‘void write_video_frame(AVFormatContext*, AVStream*)’:
video.cpp:202:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:202:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:202:13: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
c = st->codec;
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:256:20: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if (c->coded_frame->pts != AV_NOPTS_VALUE)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:256:20: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if (c->coded_frame->pts != AV_NOPTS_VALUE)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:256:20: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if (c->coded_frame->pts != AV_NOPTS_VALUE)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:257:42: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:257:42: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:257:42: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
pkt.pts= av_rescale_q(c->coded_frame->pts, c->time_base, st->time_base);
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:258:19: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if(c->coded_frame->key_frame)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:258:19: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if(c->coded_frame->key_frame)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:258:19: warning: ‘AVCodecContext::coded_frame’ is deprecated [-Wdeprecated-declarations]
if(c->coded_frame->key_frame)
^
In file included from video.cpp:8:0:
./FFmpeg/libavcodec/avcodec.h:2723:35: note: declared here
attribute_deprecated AVFrame *coded_frame;
^
video.cpp:357:40: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
av_freep(&context->streams[i]->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:357:40: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
av_freep(&context->streams[i]->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:357:40: warning: ‘AVStream::codec’ is deprecated [-Wdeprecated-declarations]
av_freep(&context->streams[i]->codec);
^
In file included from video.cpp:9:0:
./FFmpeg/libavformat/avformat.h:876:21: note: declared here
AVCodecContext *codec;
^
video.cpp:337:38: warning: ignoring return value of ‘int avformat_write_header(AVFormatContext*, AVDictionary**)’, declared with attribute warn_unused_result [-Wunused-result]
avformat_write_header(context, 0);
^
我还定义了几个宏来重新定义那些被省略的。在现代 ffmpeg API 中，它们必须被替换。
有人可以帮我解决错误和弃用警告以符合最近的 ffmpeg API 吗？
最佳答案
由于 st->codec 这种代码方式在 ffmpeg 4.0+ 版本中已经被弃用，新的方式应该重写如下。
AVFormatContext *ifmt_ctx = NULL;
// ... record sth to ifmt_ctx here ...
AVCodec *codec = avcodec_find_decoder(ifmt_ctx->streams[i]->codecpar->codec_id);
AVCodecContext *codec_ctx = avcodec_alloc_context3(codec);
我在我的项目中成功编译了它们。
关于c++ - 使用最新的 ffmpeg API (2017) 创建视频，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47321509/