git.sesse.net Git - nageru/blob - image_input.cpp

   1 #include "image_input.h"
   2
   3 #include <errno.h>
   4 #include <movit/flat_input.h>
   5 #include <movit/image_format.h>
   6 #include <stdint.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10
  11 extern "C" {
  12 #include <libavcodec/avcodec.h>
  13 #include <libavformat/avformat.h>
  14 #include <libavutil/avutil.h>
  15 #include <libavutil/error.h>
  16 #include <libavutil/frame.h>
  17 #include <libavutil/imgutils.h>
  18 #include <libavutil/mem.h>
  19 #include <libavutil/pixfmt.h>
  20 #include <libswscale/swscale.h>
  21 }
  22
  23 #include <fcntl.h>
  24 #include <sys/stat.h>
  25 #include <unistd.h>
  26 #include <cstddef>
  27 #include <functional>
  28 #include <mutex>
  29 #include <thread>
  30 #include <utility>
  31 #include <vector>
  32
  33 #include "ffmpeg_raii.h"
  34 #include "ffmpeg_util.h"
  35 #include "flags.h"
  36
  37 struct SwsContext;
  38
  39 using namespace std;
  40
  41 ImageInput::ImageInput(const string &filename)
  42         : movit::FlatInput({movit::COLORSPACE_sRGB, movit::GAMMA_sRGB}, movit::FORMAT_RGBA_POSTMULTIPLIED_ALPHA,
  43                            GL_UNSIGNED_BYTE, 1280, 720),  // Resolution will be overwritten.
  44           filename(filename),
  45           pathname(search_for_file_or_die(filename)),
  46           current_image(load_image(filename, pathname))
  47 {
  48         if (current_image == nullptr) {  // Could happen even though search_for_file() returned.
  49                 fprintf(stderr, "Couldn't load image, exiting.\n");
  50                 exit(1);
  51         }
  52         set_width(current_image->width);
  53         set_height(current_image->height);
  54         set_pixel_data(current_image->pixels.get());
  55 }
  56
  57 void ImageInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
  58 {
  59         // See if the background thread has given us a new version of our image.
  60         // Note: The old version might still be lying around in other ImageInputs
  61         // (in fact, it's likely), but at least the total amount of memory used
  62         // is bounded. Currently we don't even share textures between them,
  63         // so there's a fair amount of OpenGL memory waste anyway (the cache
  64         // is mostly there to save startup time, not RAM).
  65         {
  66                 unique_lock<mutex> lock(all_images_lock);
  67                 if (all_images[pathname] != current_image) {
  68                         current_image = all_images[pathname];
  69                         set_pixel_data(current_image->pixels.get());
  70                 }
  71         }
  72         movit::FlatInput::set_gl_state(glsl_program_num, prefix, sampler_num);
  73 }
  74
  75 shared_ptr<const ImageInput::Image> ImageInput::load_image(const string &filename, const string &pathname)
  76 {
  77         unique_lock<mutex> lock(all_images_lock);  // Held also during loading.
  78         if (all_images.count(pathname)) {
  79                 return all_images[pathname];
  80         }
  81
  82         all_images[pathname] = load_image_raw(pathname);
  83         timespec first_modified = all_images[pathname]->last_modified;
  84         update_threads[pathname] =
  85                 thread(bind(update_thread_func, filename, pathname, first_modified));
  86
  87         return all_images[pathname];
  88 }
  89
  90 shared_ptr<const ImageInput::Image> ImageInput::load_image_raw(const string &pathname)
  91 {
  92         // Note: Call before open, not after; otherwise, there's a race.
  93         // (There is now, too, but it tips the correct way. We could use fstat()
  94         // if we had the file descriptor.)
  95         struct stat buf;
  96         if (stat(pathname.c_str(), &buf) != 0) {
  97                 fprintf(stderr, "%s: Error stat-ing file\n", pathname.c_str());
  98                 return nullptr;
  99         }
 100         timespec last_modified = buf.st_mtim;
 101
 102         auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr);
 103         if (format_ctx == nullptr) {
 104                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 105                 return nullptr;
 106         }
 107
 108         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 109                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 110                 return nullptr;
 111         }
 112
 113         int stream_index = find_stream_index(format_ctx.get(), AVMEDIA_TYPE_VIDEO);
 114         if (stream_index == -1) {
 115                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 116                 return nullptr;
 117         }
 118
 119         const AVCodecParameters *codecpar = format_ctx->streams[stream_index]->codecpar;
 120         AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 121         if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 122                 fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
 123                 return nullptr;
 124         }
 125         AVCodec *codec = avcodec_find_decoder(codecpar->codec_id);
 126         if (codec == nullptr) {
 127                 fprintf(stderr, "%s: Cannot find decoder\n", pathname.c_str());
 128                 return nullptr;
 129         }
 130         if (avcodec_open2(codec_ctx.get(), codec, nullptr) < 0) {
 131                 fprintf(stderr, "%s: Cannot open decoder\n", pathname.c_str());
 132                 return nullptr;
 133         }
 134         unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
 135                 codec_ctx.get(), avcodec_close);
 136
 137         // Read packets until we have a frame or there are none left.
 138         int frame_finished = 0;
 139         AVFrameWithDeleter frame = av_frame_alloc_unique();
 140         bool eof = false;
 141         do {
 142                 AVPacket pkt;
 143                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 144                         &pkt, av_packet_unref);
 145                 av_init_packet(&pkt);
 146                 pkt.data = nullptr;
 147                 pkt.size = 0;
 148                 if (av_read_frame(format_ctx.get(), &pkt) == 0) {
 149                         if (pkt.stream_index != stream_index) {
 150                                 continue;
 151                         }
 152                         if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
 153                                 fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
 154                                 return nullptr;
 155                         }
 156                 } else {
 157                         eof = true;  // Or error, but ignore that for the time being.
 158                 }
 159
 160                 int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
 161                 if (err == 0) {
 162                         frame_finished = true;
 163                         break;
 164                 } else if (err != AVERROR(EAGAIN)) {
 165                         fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
 166                         return nullptr;
 167                 }
 168         } while (!eof);
 169
 170         if (!frame_finished) {
 171                 fprintf(stderr, "%s: Decoder did not output frame.\n", pathname.c_str());
 172                 return nullptr;
 173         }
 174
 175         uint8_t *pic_data[4] = {nullptr};
 176         unique_ptr<uint8_t *, decltype(av_freep)*> pic_data_cleanup(
 177                 &pic_data[0], av_freep);
 178         int linesizes[4];
 179         if (av_image_alloc(pic_data, linesizes, frame->width, frame->height, AV_PIX_FMT_RGBA, 1) < 0) {
 180                 fprintf(stderr, "%s: Could not allocate picture data\n", pathname.c_str());
 181                 return nullptr;
 182         }
 183         unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(
 184                 sws_getContext(frame->width, frame->height,
 185                         (AVPixelFormat)frame->format, frame->width, frame->height,
 186                         AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr),
 187                 sws_freeContext);
 188         if (sws_ctx == nullptr) {
 189                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
 190                 return nullptr;
 191         }
 192         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 193
 194         size_t len = frame->width * frame->height * 4;
 195         unique_ptr<uint8_t[]> image_data(new uint8_t[len]);
 196         av_image_copy_to_buffer(image_data.get(), len, pic_data, linesizes, AV_PIX_FMT_RGBA, frame->width, frame->height, 1);
 197
 198         shared_ptr<Image> image(new Image{unsigned(frame->width), unsigned(frame->height), move(image_data), last_modified});
 199         return image;
 200 }
 201
 202 // Fire up a thread to update the image every second.
 203 // We could do inotify, but this is good enough for now.
 204 void ImageInput::update_thread_func(const std::string &filename, const std::string &pathname, const timespec &first_modified)
 205 {
 206         char thread_name[16];
 207         snprintf(thread_name, sizeof(thread_name), "Update_%s", filename.c_str());
 208         pthread_setname_np(pthread_self(), thread_name);
 209
 210         timespec last_modified = first_modified;
 211         struct stat buf;
 212         for ( ;; ) {
 213                 {
 214                         unique_lock<mutex> lock(threads_should_quit_mu);
 215                         threads_should_quit_modified.wait_for(lock, chrono::seconds(1), []() { return threads_should_quit; });
 216                 }
 217
 218                 if (threads_should_quit) {
 219                         return;
 220                 }
 221
 222                 if (stat(pathname.c_str(), &buf) != 0) {
 223                         fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
 224                         continue;
 225                 }
 226                 if (buf.st_mtim.tv_sec == last_modified.tv_sec &&
 227                     buf.st_mtim.tv_nsec == last_modified.tv_nsec) {
 228                         // Not changed.
 229                         continue;
 230                 }
 231                 shared_ptr<const Image> image = load_image_raw(pathname);
 232                 if (image == nullptr) {
 233                         fprintf(stderr, "Couldn't load image, leaving the old in place.\n");
 234                         continue;
 235                 }
 236                 fprintf(stderr, "Loaded new version of %s from disk.\n", pathname.c_str());
 237                 unique_lock<mutex> lock(all_images_lock);
 238                 all_images[pathname] = image;
 239                 last_modified = image->last_modified;
 240         }
 241 }
 242
 243 void ImageInput::shutdown_updaters()
 244 {
 245         {
 246                 unique_lock<mutex> lock(threads_should_quit_mu);
 247                 threads_should_quit = true;
 248                 threads_should_quit_modified.notify_all();
 249         }
 250         for (auto &it : update_threads) {
 251                 it.second.join();
 252         }
 253 }
 254
 255 mutex ImageInput::all_images_lock;
 256 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 257 map<string, thread> ImageInput::update_threads;
 258 mutex ImageInput::threads_should_quit_mu;
 259 bool ImageInput::threads_should_quit = false;
 260 condition_variable ImageInput::threads_should_quit_modified;