ffmpeg/test.c

   1 #include <libavcodec/avcodec.h>
   2 #include <libavformat/avformat.h>
   3 #include <libswscale/swscale.h>
   4
   5 char const video[] = "/home/carl/Films/A town called panic.divx";//Ghostbusters.avi";
   6
   7 static void
   8 save_frame (AVFrame *frame, int width, int height, int N)
   9 {
  10         char filename[32];
  11
  12         sprintf (filename, "frame%d.ppm", N);
  13         FILE* file = fopen (filename, "wb");
  14         if (file == NULL) {
  15                 return;
  16         }
  17
  18         fprintf (file, "P6\n%d %d\n255\n", width, height);
  19
  20         for (int y = 0; y < height; y++) {
  21                 fwrite (frame->data[0] + y * frame->linesize[0], 1, width * 3, file);
  22         }
  23
  24         fclose (file);
  25 }
  26
  27 int
  28 main (int argc, char* argv[])
  29 {
  30         av_register_all ();
  31
  32         AVFormatContext* format_context = NULL;
  33         if (avformat_open_input (&format_context, video, NULL, NULL) != 0) {
  34                 fprintf (stderr, "avformat_open_input failed.\n");
  35                 return -1;
  36         }
  37
  38         if (avformat_find_stream_info (format_context, NULL) < 0) {
  39                 fprintf (stderr, "av_find_stream_info failed.\n");
  40                 return -1;
  41         }
  42
  43         av_dump_format (format_context, 0, video, 0);
  44
  45         int video_stream = -1;
  46         for (uint32_t i = 0; i < format_context->nb_streams; ++i) {
  47                 if (format_context->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
  48                         video_stream = i;
  49                         break;
  50                 }
  51         }
  52
  53         AVCodecContext* codec_context = format_context->streams[video_stream]->codec;
  54
  55         AVCodec* codec = avcodec_find_decoder (codec_context->codec_id);
  56         if (codec == NULL) {
  57                 fprintf (stderr, "avcodec_find_decoder failed.\n");
  58                 return -1;
  59         }
  60
  61         if (avcodec_open2 (codec_context, codec, NULL) < 0) {
  62                 fprintf (stderr, "avcodec_open failed.\n");
  63                 return -1;
  64         }
  65
  66         if (codec_context->time_base.num > 1000 && codec_context->time_base.den == 1) {
  67                 codec_context->time_base.den = 1000;
  68         }
  69
  70         AVFrame* frame = avcodec_alloc_frame ();
  71
  72         AVFrame* frame_RGB = avcodec_alloc_frame ();
  73         if (frame_RGB == NULL) {
  74                 fprintf (stderr, "avcodec_alloc_frame failed.\n");
  75                 return -1;
  76         }
  77
  78         int num_bytes = avpicture_get_size (PIX_FMT_RGB24, codec_context->width, codec_context->height);
  79         uint8_t* buffer = (uint8_t *) malloc (num_bytes);
  80
  81         avpicture_fill ((AVPicture *) frame_RGB, buffer, PIX_FMT_RGB24, codec_context->width, codec_context->height);
  82
  83         int i = 0;
  84         AVPacket packet;
  85         while (av_read_frame (format_context, &packet) >= 0) {
  86
  87                 int frame_finished;
  88
  89                 if (packet.stream_index == video_stream) {
  90                         avcodec_decode_video2 (codec_context, frame, &frame_finished, &packet);
  91
  92                         if (frame_finished) {
  93                                 static struct SwsContext *img_convert_context;
  94
  95                                 if (img_convert_context == NULL) {
  96                                         int w = codec_context->width;
  97                                         int h = codec_context->height;
  98
  99                                         img_convert_context = sws_getContext (
 100                                                 w, h,
 101                                                 codec_context->pix_fmt,
 102                                                 w, h, PIX_FMT_RGB24, SWS_BICUBIC,
 103                                                 NULL, NULL, NULL
 104                                                 );
 105
 106                                         if (img_convert_context == NULL) {
 107                                                 fprintf (stderr, "sws_getContext failed.\n");
 108                                                 return -1;
 109                                         }
 110                                 }
 111
 112                                 sws_scale (
 113                                         img_convert_context, frame->data, frame->linesize, 0,
 114                                         codec_context->height, frame_RGB->data, frame_RGB->linesize
 115                                         );
 116
 117                                 ++i;
 118                                 if (i > 100 && i < 150) {
 119                                         save_frame (frame_RGB, codec_context->width, codec_context->height, i);
 120                                 }
 121                         }
 122                 }
 123
 124                 av_free_packet (&packet);
 125         }
 126
 127         free (buffer);
 128         av_free (frame_RGB);
 129         av_free (frame);
 130         avcodec_close(codec_context);
 131         avformat_close_input (&format_context);
 132
 133         return 0;
 134 }