有没有办法从Android上的一系列图像创建视频？也许是一种扩展MediaRecorder并能够将图像作为输入的方法。
我尝试真正创建视频并存储它（例如，作为mpeg4文件）。
感谢您的任何建议。
答案 0 :(得分：7)
我也在尝试做同样的事情。我一直建议使用Libav。 http://libav.org/ 但是我需要用NDK构建它，我目前有一些问题。
我正在寻找一些关于它的文档。我会告诉你的。
我已经创建了一篇关于它的帖子：Libav build for Android
答案 1 :(得分：1)
您可以在ImageView中使用AnimationDrawable。
使用AnimationDrawable.addFrame(Drawable frame, int duration)方法添加框架，然后使用AnimationDrawable.start()启动动画。
不确定这是否理想，但它会起作用。
答案 2 :(得分：1)
我使用Android + NDK
AVFrame* OpenImage(const char* imageFileName)
{
AVFormatContext *pFormatCtx = avformat_alloc_context();
std::cout<<"1"<<imageFileName<<std::endl;
if( avformat_open_input(&pFormatCtx, imageFileName, NULL, NULL) < 0)
{
printf("Can't open image file '%s'\n", imageFileName);
return NULL;
}
std::cout<<"2"<<std::endl;
av_dump_format(pFormatCtx, 0, imageFileName, false);
AVCodecContext *pCodecCtx;
std::cout<<"3"<<std::endl;
pCodecCtx = pFormatCtx->streams[0]->codec;
pCodecCtx->width = W_VIDEO;
pCodecCtx->height = H_VIDEO;
//pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
// Find the decoder for the video stream
AVCodec *pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
if (!pCodec)
{
printf("Codec not found\n");
return NULL;
}
// Open codec
//if(avcodec_open2(pCodecCtx, pCodec)<0)
if(avcodec_open2(pCodecCtx, pCodec,NULL)<0)//check this NULL, it should be of AVDictionary **options
{
printf("Could not open codec\n");
return NULL;
}
std::cout<<"4"<<std::endl;
//
AVFrame *pFrame;
pFrame = av_frame_alloc();
if (!pFrame)
{
printf("Can't allocate memory for AVFrame\n");
return NULL;
}
printf("here");
int frameFinished;
int numBytes;
// Determine required buffer size and allocate buffer
numBytes = avpicture_get_size( pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
uint8_t *buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));
avpicture_fill((AVPicture *) pFrame, buffer, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
// Read frame
AVPacket packet;
int framesNumber = 0;
while (av_read_frame(pFormatCtx, &packet) >= 0)
{
if(packet.stream_index != 0)
continue;
int ret = avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
if (ret > 0)
{
printf("Frame is decoded, size %d\n", ret);
pFrame->quality = 4;
return pFrame;
}
else
printf("Error [%d] while decoding frame: %s\n", ret, strerror(AVERROR(ret)));
}
}
int combine_images_to_video(const char * infile_dir, const char * infile_prefix, const char* infile_surname, int total_frames,const char *outfile)
{
if (total_frames <= 0){
std::cout << "Usage: cv2ff <dir_name> <prefix> <image surname> <total frames> <outfile>" << std::endl;
std::cout << "Please check that the 4th argument is integer value of total frames"<<std::endl;
return 1;
}
printf("max %d frames\n",total_frames);
char *imageFileName;
char numberChar[NUMNUMBER];
// initialize FFmpeg library
av_register_all();
// av_log_set_level(AV_LOG_DEBUG);
int ret;
const int dst_width = W_VIDEO;
const int dst_height = H_VIDEO;
const AVRational dst_fps = {30, 1};//{fps,1}
// open output format context
AVFormatContext* outctx = nullptr;
ret = avformat_alloc_output_context2(&outctx, nullptr, nullptr, outfile);
//outctx->video_codec->
if (ret < 0) {
std::cerr << "fail to avformat_alloc_output_context2(" << outfile << "): ret=" << ret;
return 2;
}
// open output IO context
ret = avio_open2(&outctx->pb, outfile, AVIO_FLAG_WRITE, nullptr, nullptr);
if (ret < 0) {
std::cerr << "fail to avio_open2: ret=" << ret;
return 2;
}
// create new video stream
AVCodec* vcodec = avcodec_find_encoder(outctx->oformat->video_codec);
AVStream* vstrm = avformat_new_stream(outctx, vcodec);
if (!vstrm) {
std::cerr << "fail to avformat_new_stream";
return 2;
}
avcodec_get_context_defaults3(vstrm->codec, vcodec);
vstrm->codec->width = dst_width;
vstrm->codec->height = dst_height;
vstrm->codec->pix_fmt = vcodec->pix_fmts[0];
vstrm->codec->time_base = vstrm->time_base = av_inv_q(dst_fps);
vstrm->r_frame_rate = vstrm->avg_frame_rate = dst_fps;
if (outctx->oformat->flags & AVFMT_GLOBALHEADER)
vstrm->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
// open video encoder
ret = avcodec_open2(vstrm->codec, vcodec, nullptr);
if (ret < 0) {
std::cerr << "fail to avcodec_open2: ret=" << ret;
return 2;
}
std::cout
<< "outfile: " << outfile << "\n"
<< "format: " << outctx->oformat->name << "\n"
<< "vcodec: " << vcodec->name << "\n"
<< "size: " << dst_width << 'x' << dst_height << "\n"
<< "fps: " << av_q2d(dst_fps) << "\n"
<< "pixfmt: " << av_get_pix_fmt_name(vstrm->codec->pix_fmt) << "\n"
<< std::flush;
// initialize sample scaler
SwsContext* swsctx = sws_getCachedContext(
nullptr, dst_width, dst_height, AV_PIX_FMT_BGR24,
dst_width, dst_height, vstrm->codec->pix_fmt, SWS_BICUBIC, nullptr, nullptr, nullptr);
if (!swsctx) {
std::cerr << "fail to sws_getCachedContext";
return 2;
}
// allocate frame buffer for encoding
AVFrame* frame = av_frame_alloc();
std::vector<uint8_t> framebuf(avpicture_get_size(vstrm->codec->pix_fmt, dst_width, dst_height));
avpicture_fill(reinterpret_cast<AVPicture*>(frame), framebuf.data(), vstrm->codec->pix_fmt, dst_width, dst_height);
frame->width = dst_width;
frame->height = dst_height;
frame->format = static_cast<int>(vstrm->codec->pix_fmt);
// encoding loop
avformat_write_header(outctx, nullptr);
int64_t frame_pts = 0;
unsigned nb_frames = 0;
bool end_of_stream = false;
int got_pkt = 0;
int i =0;
imageFileName = (char *)malloc(strlen(infile_dir)+strlen(infile_prefix)+NUMNUMBER+strlen(infile_surname)+1);
do{
if(!end_of_stream){
strcpy(imageFileName,infile_dir);
//strcat(imageFileName,"/");
strcat(imageFileName,infile_prefix);
sprintf(numberChar,"%03d",i+1);
strcat(imageFileName,numberChar);
//strcat(imageFileName,".");
strcat(imageFileName,infile_surname);
__android_log_print(1, "RecordingImage", "%s", imageFileName);
std::cout<<imageFileName<<std::endl;
AVFrame* frame_from_file = OpenImage(imageFileName);
if(!frame_from_file){
std::cout<<"error OpenImage"<<std::endl;
return 5;
}
//const int Stride [] = {1920};
sws_scale(swsctx, frame_from_file->data, &STRIDE , 0, frame_from_file->height, frame->data, frame->linesize);
frame->pts = frame_pts++;
av_frame_free(&frame_from_file);
}
// encode video frame
AVPacket pkt;
pkt.data = nullptr;
pkt.size = 0;
av_init_packet(&pkt);
ret = avcodec_encode_video2(vstrm->codec, &pkt, end_of_stream ? nullptr : frame, &got_pkt);
if (ret < 0) {
std::cerr << "fail to avcodec_encode_video2: ret=" << ret << "\n";
return 2;
}
// rescale packet timestamp
pkt.duration = 1;
av_packet_rescale_ts(&pkt, vstrm->codec->time_base, vstrm->time_base);
// write packet
av_write_frame(outctx, &pkt);
std::cout << nb_frames << '\r' << std::flush; // dump progress
++nb_frames;
av_free_packet(&pkt);
i++;
if(i==total_frames-1)
end_of_stream = true;
} while (i<total_frames);
av_write_trailer(outctx);
std::cout << nb_frames << " frames encoded" << std::endl;
av_frame_free(&frame);
avcodec_close(vstrm->codec);
avio_close(outctx->pb);
avformat_free_context(outctx);
free(imageFileName);
return 0;
}
答案 3 :(得分：0)
我们可以使用ffmpeg从图像创建视频。
查看我的post在android中使用ffmpeg。
使用以下命令从放置在同一文件夹中的图像创建视频
String command[]={"-y", "-r","1/5" ,"-i",src.getAbsolutePath(),
"-c:v","libx264","-vf", "fps=25","-pix_fmt","yuv420p", dest.getAbsolutePath()};
在这里，
src.getAbsolutePath（）是所有输入图像的绝对路径。
例如， 如果所有图像都存储在带有名称的Pictures目录内的Images文件夹中 extract_picture001.jpg，extract_picture002.jpg，extract_picture003.jpg ......
。 然后，
String filePrefix = "extract_picture";
String fileExtn = ".jpg";
File picDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File dir = new File(picDir, "Images");
File src = new File(dir, filePrefix + "%03d" + fileExtn);
用于从放置在不同文件夹中的图像创建视频 必须创建一个文本文件并添加图像路径，然后指定 该文本文件的路径作为输入选项。 例如，
文字档案
file '/storage/emulated/0/DCIM/Camera/P_20170807_143916.jpg'
duration 2
file '/storage/emulated/0/DCIM/Pic/P_20170305_142948.jpg'
duration 5
file '/storage/emulated/0/DCIM/Camera/P_20170305_142939.jpg'
duration 6
file '/storage/emulated/0/DCIM/Pic/P_20170305_142818.jpg'
duration 2
命令
String command[] = {"-y", "-f", "concat", "-safe", "0", "-i", textFile.getAbsolutePath(), "-vsync", "vfr", "-pix_fmt", "yuv420p", dest.getAbsolutePath()};
其中textFile.getAbsolutePath（）是文本文件的绝对路径
查看此ffmpeg doc了解更多信息