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path: root/src/plugins/thumbnailffmpeg_extractor.c
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/*
     This file is part of libextractor.
     Copyright (C) 2008, 2012 Heikki Lindholm and Christian Grothoff

     libextractor is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     libextractor is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with libextractor; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
 */
/**
 * @file thumbnailffmpeg_extractor.c
 * @author Heikki Lindholm
 * @author Christian Grothoff
 * @brief this extractor produces a binary encoded
 * thumbnail of images and videos using the ffmpeg libs.
 *
 * This is a thumbnail extractor using the ffmpeg libraries that will eventually
 * support extracting thumbnails from both image and video files. 
 *
 * Note that ffmpeg has a few issues:
 * (1) there are no recent official releases of the ffmpeg libs
 * (2) ffmpeg has a history of having security issues (parser is not robust)
 *
 *  So this plugin cannot be recommended for system with high security
 *requirements. 
 */
#include "platform.h"
#include "extractor.h"
#include <magic.h>

#if HAVE_LIBAVUTIL_AVUTIL_H
#include <libavutil/avutil.h>
#elif HAVE_FFMPEG_AVUTIL_H
#include <ffmpeg/avutil.h>
#endif
#if HAVE_LIBAVFORMAT_AVFORMAT_H
#include <libavformat/avformat.h>
#elif HAVE_FFMPEG_AVFORMAT_H
#include <ffmpeg/avformat.h>
#endif
#if HAVE_LIBAVCODEC_AVCODEC_H
#include <libavcodec/avcodec.h>
#elif HAVE_FFMPEG_AVCODEC_H
#include <ffmpeg/avcodec.h>
#endif
#if HAVE_LIBSWSCALE_SWSCALE_H
#include <libswscale/swscale.h>
#elif HAVE_FFMPEG_SWSCALE_H
#include <ffmpeg/swscale.h>
#endif

/**
 * Set to 1 to enable debug output.
 */ 
#define DEBUG 0

/**
 * max dimension in pixels for the thumbnail.
 */
#define MAX_THUMB_DIMENSION 128         

/**
 * Maximum size in bytes for the thumbnail.
 */
#define MAX_THUMB_BYTES (100*1024)

/**
 * Global handle to MAGIC data.
 */
static magic_t magic;


/**
 * Read callback.
 *
 * @param opaque the 'struct EXTRACTOR_ExtractContext'
 * @param buf where to write data
 * @param buf_size how many bytes to read
 * @return -1 on error (or for unknown file size)
 */
static int
read_cb (void *opaque,
	 uint8_t *buf,
	 int buf_size)
{
  struct EXTRACTOR_ExtractContext *ec = opaque;
  void *data;
  ssize_t ret;

  ret = ec->read (ec->cls, &data, buf_size);
  if (ret <= 0)
    return ret;
  memcpy (buf, data, ret);
  return ret;
}


/**
 * Seek callback.
 *
 * @param opaque the 'struct EXTRACTOR_ExtractContext'
 * @param offset where to seek
 * @param whence how to seek; AVSEEK_SIZE to return file size without seeking
 * @return -1 on error (or for unknown file size)
 */
static int64_t
seek_cb (void *opaque,
	 int64_t offset,
	 int whence)
{
  struct EXTRACTOR_ExtractContext *ec = opaque;

  if (AVSEEK_SIZE == whence)
    return ec->get_size (ec->cls);
  return ec->seek (ec->cls, offset, whence);
}


/**
 * Rescale and encode a PNG thumbnail.
 *
 * @param src_width source image width
 * @param src_height source image height
 * @param src_stride 
 * @param src_pixfmt
 * @param src_data source data
 * @param dst_width desired thumbnail width
 * @param dst_height desired thumbnail height
 * @param output_data where to store the resulting PNG data
 * @param output_max_size maximum size of result that is allowed
 * @return the number of bytes used, 0 on error
 */
static size_t 
create_thumbnail (int src_width, int src_height, 
		  int src_stride[],
		  enum PixelFormat src_pixfmt, 
		  const uint8_t * const src_data[],
		  int dst_width, int dst_height,
		  uint8_t **output_data, 
		  size_t output_max_size)
{
  AVCodecContext *encoder_codec_ctx;
  AVDictionary *opts;
  AVCodec *encoder_codec;
  struct SwsContext *scaler_ctx;
  AVFrame *dst_frame;
  uint8_t *dst_buffer;
  uint8_t *encoder_output_buffer;
  size_t encoder_output_buffer_size;
  int err;

  if (NULL == (encoder_codec = avcodec_find_encoder_by_name ("png")))
    {
#if DEBUG
      fprintf (stderr,
	       "Couldn't find a PNG encoder\n");
#endif
      return 0;
    }

  /* NOTE: the scaler will be used even if the src and dst image dimensions
   * match, because the scaler will also perform colour space conversion */
  if (NULL == 
      (scaler_ctx =
       sws_getContext (src_width, src_height, src_pixfmt,
		       dst_width, dst_height, PIX_FMT_RGB24, 
		       SWS_BILINEAR, NULL, NULL, NULL)))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to get a scaler context\n");
#endif
      return 0;
    }

  if (NULL == (dst_frame = avcodec_alloc_frame ()))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate the destination image frame\n");
#endif
      sws_freeContext (scaler_ctx);
      return 0;
    }
  if (NULL == (dst_buffer =
	       av_malloc (avpicture_get_size (PIX_FMT_RGB24, dst_width, dst_height))))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate the destination image buffer\n");
#endif
      av_free (dst_frame);
      sws_freeContext (scaler_ctx);
      return 0;
    }
  avpicture_fill ((AVPicture *) dst_frame, dst_buffer,
                  PIX_FMT_RGB24, dst_width, dst_height);
  sws_scale (scaler_ctx,
             src_data, 
             src_stride,
             0, src_height, 
             dst_frame->data, 
             dst_frame->linesize);

  encoder_output_buffer_size = output_max_size;
  if (NULL == (encoder_output_buffer = av_malloc (encoder_output_buffer_size)))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate the encoder output buffer\n");
#endif
      av_free (dst_buffer);
      av_free (dst_frame);
      sws_freeContext (scaler_ctx);
      return 0;
    }

  if (NULL == (encoder_codec_ctx = avcodec_alloc_context3 (encoder_codec)))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate the encoder codec context\n");
#endif
      av_free (encoder_output_buffer);
      av_free (dst_buffer);
      av_free (dst_frame);
      sws_freeContext (scaler_ctx);
      return 0;
    }
  encoder_codec_ctx->width = dst_width;
  encoder_codec_ctx->height = dst_height;
  encoder_codec_ctx->pix_fmt = PIX_FMT_RGB24;
  opts = NULL;
  if (avcodec_open2 (encoder_codec_ctx, encoder_codec, &opts) < 0)
    {
#if DEBUG
      fprintf (stderr,
               "Failed to open the encoder\n");
#endif
      av_free (encoder_codec_ctx);
      av_free (encoder_output_buffer);
      av_free (dst_buffer);
      av_free (dst_frame);
      sws_freeContext  (scaler_ctx);
      return 0;
    }
  err = avcodec_encode_video (encoder_codec_ctx,
                              encoder_output_buffer,
                              encoder_output_buffer_size, dst_frame);
  av_dict_free (&opts);
  avcodec_close (encoder_codec_ctx);
  av_free (encoder_codec_ctx);
  av_free (dst_buffer);
  av_free (dst_frame);
  sws_freeContext (scaler_ctx);
  *output_data = encoder_output_buffer;

  return err < 0 ? 0 : err;
}



/**
 * calculate the thumbnail dimensions, taking pixel aspect into account 
 *
 * @param src_width source image width
 * @param src_height source image height
 * @param src_sar_num
 * @param src_sar_den
 * @param dst_width desired thumbnail width (set)
 * @param dst_height desired thumbnail height (set)
  */
static void 
calculate_thumbnail_dimensions (int src_width,
				int src_height,
				int src_sar_num,
				int src_sar_den,
				int *dst_width,
				int *dst_height)
{
  if ( (src_sar_num <= 0) || (src_sar_den <= 0) )
    {
      src_sar_num = 1;
      src_sar_den = 1;
    }
  if ((src_width * src_sar_num) / src_sar_den > src_height)
    {
      *dst_width = MAX_THUMB_DIMENSION;
      *dst_height = (*dst_width * src_height) /
                     ((src_width * src_sar_num) / src_sar_den);
    }
  else
    {
      *dst_height = MAX_THUMB_DIMENSION;
      *dst_width = (*dst_height *
                    ((src_width * src_sar_num) / src_sar_den)) /
                    src_height;
    }
  if (*dst_width < 8)
    *dst_width = 8;
  if (*dst_height < 1)
    *dst_height = 1;
#if DEBUG
  fprintf (stderr,
           "Thumbnail dimensions: %d %d\n", 
           *dst_width, *dst_height);
#endif
}


/**
 * Perform thumbnailing when the input is an image.
 *
 * @param image_codec_id ffmpeg codec for the image format
 * @param ec extraction context to use
 */
static void
extract_image (enum CodecID image_codec_id,
               struct EXTRACTOR_ExtractContext *ec)
{
  AVDictionary *opts;
  AVCodecContext *codec_ctx;
  AVCodec *codec;
  AVPacket avpkt;
  AVFrame *frame;
  uint8_t *encoded_thumbnail;
  int thumb_width;
  int thumb_height;
  int err;
  int frame_finished;
  ssize_t iret;
  void *data;

  if (NULL == (codec = avcodec_find_decoder (image_codec_id)))
    {
#if DEBUG
      fprintf (stderr,
               "No suitable codec found\n");
#endif
      return;
    }
  if (NULL == (codec_ctx = avcodec_alloc_context3 (codec)))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate codec context\n");
#endif
      return;
    }
  opts = NULL;
  if (0 != avcodec_open2 (codec_ctx, codec, &opts))
    {
#if DEBUG
      fprintf (stderr,
	       "Failed to open image codec\n");
#endif
      av_free (codec_ctx);
      return;
    }
  av_dict_free (&opts);
  if (NULL == (frame = avcodec_alloc_frame ()))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate frame\n");
#endif
      avcodec_close (codec_ctx);
      av_free (codec_ctx);
      return;
    }

  frame_finished = 0;
  while (! frame_finished)
    {
      if (0 >= (iret = ec->read (ec->cls,
				 &data,
				 32 * 1024)))
	break;      
      av_init_packet (&avpkt);
      avpkt.data = data;
      avpkt.size = iret;
      avcodec_decode_video2 (codec_ctx, frame, &frame_finished, &avpkt);
    }
  if (! frame_finished)
    {
#if DEBUG
      fprintf (stderr,
	       "Failed to decode a complete frame\n");
#endif
      av_free (frame);
      avcodec_close (codec_ctx);
      av_free (codec_ctx);
      return;
    }
  calculate_thumbnail_dimensions (codec_ctx->width, codec_ctx->height,
                                  codec_ctx->sample_aspect_ratio.num,
                                  codec_ctx->sample_aspect_ratio.den,
                                  &thumb_width, &thumb_height);

  err = create_thumbnail (codec_ctx->width, codec_ctx->height,
                          frame->linesize, codec_ctx->pix_fmt, 
			  (const uint8_t * const*) frame->data,
                          thumb_width, thumb_height,
                          &encoded_thumbnail, MAX_THUMB_BYTES);
  if (err > 0)
    {
      ec->proc (ec->cls,
		"thumbnailffmpeg",
		EXTRACTOR_METATYPE_THUMBNAIL,
		EXTRACTOR_METAFORMAT_BINARY,
		"image/png",
		(const char*) encoded_thumbnail,
		err);
      av_free (encoded_thumbnail);
    }
  av_free (frame);
  avcodec_close (codec_ctx);
  av_free (codec_ctx);
}


/**
 * Perform thumbnailing when the input is a video
 *
 * @param ec extraction context to use
 */
static void
extract_video (struct EXTRACTOR_ExtractContext *ec)
{
  AVPacket packet;
  AVIOContext *io_ctx;
  struct AVFormatContext *format_ctx;
  AVCodecContext *codec_ctx;
  AVCodec *codec;
  AVDictionary *options;
  AVFrame *frame;
  uint8_t *encoded_thumbnail;
  int video_stream_index;
  int thumb_width;
  int thumb_height;
  int i;
  int err;
  int frame_finished;
  unsigned char *iob;

  if (NULL == (iob = av_malloc (16 * 1024)))
    return;
  if (NULL == (io_ctx = avio_alloc_context (iob, 16 * 1024,
					    0, ec, 
					    &read_cb,
					    NULL /* no writing */,
					    &seek_cb)))
    {
      av_free (iob);
      return;
    }
  if (NULL == (format_ctx = avformat_alloc_context ()))
    {
      av_free (io_ctx);
      return;
    }
  format_ctx->pb = io_ctx;
  options = NULL;
  if (0 != avformat_open_input (&format_ctx, "<no file>", NULL, &options))
    return;
  av_dict_free (&options);  
  if (0 > avformat_find_stream_info (format_ctx, NULL))
    {
 #if DEBUG
      fprintf (stderr,
               "Failed to read stream info\n");
#endif
      avformat_close_input (&format_ctx);
      av_free (io_ctx);
      return;
    }
  codec = NULL;
  codec_ctx = NULL;
  video_stream_index = -1;
  for (i=0; i<format_ctx->nb_streams; i++)
    {
      codec_ctx = format_ctx->streams[i]->codec;
      if (AVMEDIA_TYPE_VIDEO != codec_ctx->codec_type)
        continue;
      if (NULL == (codec = avcodec_find_decoder (codec_ctx->codec_id)))
        continue;
      options = NULL;
      if (0 != (err = avcodec_open2 (codec_ctx, codec, &options)))
        {
          codec = NULL;
          continue;
        }
      av_dict_free (&options); 
      video_stream_index = i;
      break;
    }
  if ( (-1 == video_stream_index) ||
       (0 == codec_ctx->width) || 
       (0 == codec_ctx->height) )
    {
#if DEBUG
      fprintf (stderr,
               "No video streams or no suitable codec found\n");
#endif
      if (NULL != codec)
        avcodec_close (codec_ctx);
      avformat_close_input (&format_ctx);
      av_free (io_ctx);
      return;
    }

  if (NULL == (frame = avcodec_alloc_frame ()))
    {
#if DEBUG
      fprintf (stderr,
               "Failed to allocate frame\n");
#endif
      avcodec_close (codec_ctx);
      avformat_close_input (&format_ctx);
      av_free (io_ctx);
      return;
    }
#if DEBUG
  if (format_ctx->duration == AV_NOPTS_VALUE)
    fprintf (stderr,
	     "Duration unknown\n");
  else
    fprintf (stderr,
	     "Duration: %lld\n", 
	     format_ctx->duration);      
#endif
  /* TODO: if duration is known, seek to some better place,
   * but use 10 sec into stream for now */
  err = av_seek_frame (format_ctx, -1, 10 * AV_TIME_BASE, 0);
  if (err >= 0)        
    avcodec_flush_buffers (codec_ctx);        
  frame_finished = 0;

  while (1)
    {
      err = av_read_frame (format_ctx, &packet);
      if (err < 0)
        break;
      if (packet.stream_index == video_stream_index)
        {
          avcodec_decode_video2 (codec_ctx,
				 frame,
				 &frame_finished,
				 &packet);
          if (frame_finished && frame->key_frame)
            {
              av_free_packet (&packet);
              break;
            }
        }
      av_free_packet (&packet);
    }

  if (! frame_finished)
    {
#if DEBUG
      fprintf (stderr,
	       "Failed to decode a complete frame\n");
#endif
      av_free (frame);
      avcodec_close (codec_ctx);
      avformat_close_input (&format_ctx);
      av_free (io_ctx);
      return;
    }
  calculate_thumbnail_dimensions (codec_ctx->width, codec_ctx->height,
                                  codec_ctx->sample_aspect_ratio.num,
                                  codec_ctx->sample_aspect_ratio.den,
                                  &thumb_width, &thumb_height);
  err = create_thumbnail (codec_ctx->width, codec_ctx->height,
                          frame->linesize, codec_ctx->pix_fmt,
			  (const uint8_t* const *) frame->data,
                          thumb_width, thumb_height,
                          &encoded_thumbnail, MAX_THUMB_BYTES);
  if (err > 0)
    {
      ec->proc (ec->cls,
		"thumbnailffmpeg",
		EXTRACTOR_METATYPE_THUMBNAIL,
		EXTRACTOR_METAFORMAT_BINARY,
		"image/png",
		(const char*) encoded_thumbnail,
		err);
      av_free (encoded_thumbnail);
    }
  av_free (frame);
  avcodec_close (codec_ctx);
  avformat_close_input (&format_ctx);
  av_free (io_ctx);
}


/**
 * Pair of mime type and ffmpeg decoder ID.
 */
struct MIMEToDecoderMapping
{
  /**
   * String for a mime type.
   */
  const char *mime_type;

  /**
   * Corresponding ffmpeg decoder ID.
   */
  enum CodecID codec_id;
};


/**
 * map MIME image types to an ffmpeg decoder 
 */
static const struct MIMEToDecoderMapping m2d_map[] = 
  {
    { "image/x-bmp", CODEC_ID_BMP },
    { "image/gif", CODEC_ID_GIF },
    { "image/jpeg", CODEC_ID_MJPEG },
    { "image/png", CODEC_ID_PNG },
    { "image/x-png", CODEC_ID_PNG },
    { "image/x-portable-pixmap", CODEC_ID_PPM },
    { NULL, CODEC_ID_NONE }
  };


/**
 * Main method for the ffmpeg-thumbnailer plugin.
 *
 * @param ec extraction context
 */
void 
EXTRACTOR_thumbnailffmpeg_extract_method (struct EXTRACTOR_ExtractContext *ec)
{
  unsigned int i;
  ssize_t iret;
  void *data;
  const char *mime;

  if (-1 == (iret = ec->read (ec->cls,
			      &data,
			      16 * 1024)))
    return;
  if (NULL == (mime = magic_buffer (magic, data, iret)))
    return;
  if (0 != ec->seek (ec->cls, 0, SEEK_SET))
    return;
  for (i = 0; NULL != m2d_map[i].mime_type; i++)
    if (0 == strcmp (m2d_map[i].mime_type, mime))
      {
	extract_image (m2d_map[i].codec_id, ec);
	return;
      }
  extract_video (ec);
}


/**
 * This plugin sometimes is installed under the alias 'thumbnail'.
 * So we need to provide a second entry method.
 *
 * @param ec extraction context
 */
void 
EXTRACTOR_thumbnail_extract_method (struct EXTRACTOR_ExtractContext *ec)
{
  EXTRACTOR_thumbnailffmpeg_extract_method (ec);
}


/**
 * Log callback.  Does nothing.
 *
 * @param ptr NULL
 * @param level log level
 * @param format format string
 * @param ap arguments for format
 */
static void 
thumbnailffmpeg_av_log_callback (void* ptr, 
				 int level,
				 const char *format,
				 va_list ap)
{
#if DEBUG
  vfprintf(stderr, format, ap);
#endif
}


/**
 * Initialize av-libs and load magic file.
 */
void __attribute__ ((constructor)) 
thumbnailffmpeg_lib_init (void)
{
  av_log_set_callback (&thumbnailffmpeg_av_log_callback);
  av_register_all ();
  magic = magic_open (MAGIC_MIME_TYPE);
  if (0 != magic_load (magic, NULL))
    {
      /* FIXME: how to deal with errors? */
    }
}


/**
 * Destructor for the library, cleans up.
 */
void __attribute__ ((destructor)) 
thumbnailffmpeg_ltdl_fini () 
{
  if (NULL != magic)
    {
      magic_close (magic);
      magic = NULL;
    }
}


/* end of thumbnailffmpeg_extractor.c */