[FFmpeg-devel] avcodec/tiff: Add support for recognizing DNG files

From: Nick Renieris <velocityra@gmail.com>

Prints "DNG images are not supported" if it finds a TIFF image with
the 'DNGVersion' tag.  In DNG images with the .tiff extension, it
solves the issue where the TIFF thumbnail in IFD 0 was incorrectly
parsed (related confusion: [1]).  The user can still decode those
with the -subimage option.  Also prints the DNG version of the file
on the debug channel.

Additionally:
 - Renamed TIFF_WHITE_LEVEL to DNG_WHITE_LEVEL since it is specified
   in the DNG spec.
 - Added/changed some comments to be more precise in differentiating
   between TIFF, TIFF/EP and DNG values.

Related to ticket: https://trac.ffmpeg.org/ticket/4364

---

[1]: https://superuser.com/questions/546879/creating-video-from-dng-images-with-ffmpeg

Signed-off-by: Nick Renieris <velocityra@gmail.com>
---
 libavcodec/tiff.c  | 29 ++++++++++++++++++++++++++++-
 libavcodec/tiff.h  | 18 +++++++++++++-----
 libavformat/img2.c |  1 +
 3 files changed, 42 insertions(+), 6 deletions(-)

On 3/18/19, velocityra@gmail.com <velocityra@gmail.com> wrote:
> From: Nick Renieris <velocityra@gmail.com>
>
> Prints "DNG images are not supported" if it finds a TIFF image with
> the 'DNGVersion' tag.  In DNG images with the .tiff extension, it
> solves the issue where the TIFF thumbnail in IFD 0 was incorrectly
> parsed (related confusion: [1]).  The user can still decode those
> with the -subimage option.  Also prints the DNG version of the file
> on the debug channel.
>
> Additionally:
>  - Renamed TIFF_WHITE_LEVEL to DNG_WHITE_LEVEL since it is specified
>    in the DNG spec.
>  - Added/changed some comments to be more precise in differentiating
>    between TIFF, TIFF/EP and DNG values.
>
> Related to ticket: https://trac.ffmpeg.org/ticket/4364
>
> ---
>
> [1]:
> https://superuser.com/questions/546879/creating-video-from-dng-images-with-ffmpeg
>
> Signed-off-by: Nick Renieris <velocityra@gmail.com>
> ---
>  libavcodec/tiff.c  | 29 ++++++++++++++++++++++++++++-
>  libavcodec/tiff.h  | 18 +++++++++++++-----
>  libavformat/img2.c |  1 +
>  3 files changed, 42 insertions(+), 6 deletions(-)
>
> diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
> index 112f5b52f4..41c63900fd 100644
> --- a/libavcodec/tiff.c
> +++ b/libavcodec/tiff.c
> @@ -70,6 +70,7 @@ typedef struct TiffContext {
>      int fill_order;
>      uint32_t res[4];
>
> +    int dng_mode; /** denotes that this is a DNG image */
>      int is_bayer;
>      uint8_t pattern[4];
>      unsigned white_level;
> @@ -1077,7 +1078,7 @@ static int tiff_decode_tag(TiffContext *s, AVFrame
> *frame)
>      case TIFF_SUB_IFDS:
>          s->sub_ifd = value;
>          break;
> -    case TIFF_WHITE_LEVEL:
> +    case DNG_WHITE_LEVEL:
>          s->white_level = value;
>          break;
>      case TIFF_CFA_PATTERN_DIM:
> @@ -1322,6 +1323,20 @@ static int tiff_decode_tag(TiffContext *s, AVFrame
> *frame)
>      case TIFF_SOFTWARE_NAME:
>          ADD_METADATA(count, "software", NULL);
>          break;
> +    case DNG_VERSION:
> +        if (count == 4) {
> +            unsigned int ver[4];
> +            ver[0] = ff_tget(&s->gb, type, s->le);
> +            ver[1] = ff_tget(&s->gb, type, s->le);
> +            ver[2] = ff_tget(&s->gb, type, s->le);
> +            ver[3] = ff_tget(&s->gb, type, s->le);
> +
> +            av_log(s->avctx, AV_LOG_DEBUG, "DNG file, version
> %u.%u.%u.%u\n",
> +                ver[0], ver[1], ver[2], ver[3]);
> +
> +            s->dng_mode = 1;
> +        }
> +        break;
>      default:
>          if (s->avctx->err_recognition & AV_EF_EXPLODE) {
>              av_log(s->avctx, AV_LOG_ERROR,
> @@ -1375,6 +1390,7 @@ again:
>      s->fill_order  = 0;
>      s->white_level = 0;
>      s->is_bayer    = 0;
> +    s->dng_mode    = 0;
>      free_geotags(s);
>
>      // Reset these offsets so we can tell if they were set this frame
> @@ -1389,6 +1405,17 @@ again:
>              return ret;
>      }
>
> +    if (s->dng_mode) {
> +        av_log(avctx, AV_LOG_ERROR, "DNG images are not supported\n");
> +
> +        if (s->get_subimage) {
> +            av_log(avctx, AV_LOG_INFO, "Decoding embedded TIFF thumbnail in
> DNG image\n");
> +        } else {
> +            av_log(avctx, AV_LOG_INFO, "Consider using -subimage for
> decoding the embedded thumbail instead\n");
> +            return AVERROR_INVALIDDATA;
> +        }
> +    }
> +
>      if (s->sub_ifd && s->get_subimage) {
>          off = s->sub_ifd;
>          if (off >= UINT_MAX - 14 || avpkt->size < off + 14) {
> diff --git a/libavcodec/tiff.h b/libavcodec/tiff.h
> index 4b08650108..3cede299f6 100644
> --- a/libavcodec/tiff.h
> +++ b/libavcodec/tiff.h
> @@ -20,7 +20,7 @@
>
>  /**
>   * @file
> - * TIFF tables
> + * TIFF constants & data structures
>   *
>   * For more information about the TIFF format, check the official docs at:
>   * http://partners.adobe.com/public/developer/tiff/index.html
> @@ -33,7 +33,7 @@
>  #include <stdint.h>
>  #include "tiff_common.h"
>
> -/** abridged list of TIFF tags */
> +/** abridged list of TIFF and TIFF/EP tags */
>  enum TiffTags {
>      TIFF_SUBFILE            = 0xfe,
>      TIFF_WIDTH              = 0x100,
> @@ -85,10 +85,17 @@ enum TiffTags {
>      TIFF_GEO_KEY_DIRECTORY  = 0x87AF,
>      TIFF_GEO_DOUBLE_PARAMS  = 0x87B0,
>      TIFF_GEO_ASCII_PARAMS   = 0x87B1,
> -    TIFF_WHITE_LEVEL        = 0xC61D,
>  };
>
> -/** list of TIFF compression types */
> +/** abridged list of DNG tags */
> +enum DngTags
> +{
> +    DNG_VERSION             = 0xC612,
> +    DNG_BACKWARD_VERSION    = 0xC613,
> +    DNG_WHITE_LEVEL         = 0xC61D,
> +};
> +
> +/** list of TIFF, TIFF/EP and DNG compression types */
>  enum TiffCompr {
>      TIFF_RAW = 1,
>      TIFF_CCITT_RLE,
> @@ -151,6 +158,7 @@ enum TiffGeoTagKey {
>      TIFF_VERTICAL_UNITS_GEOKEY               = 4099
>  };
>
> +/** list of TIFF, TIFF/AP and DNG PhotometricInterpretation
> (TIFF_PHOTOMETRIC) values */
>  enum TiffPhotometric {
>      TIFF_PHOTOMETRIC_NONE       = -1,
>      TIFF_PHOTOMETRIC_WHITE_IS_ZERO,      /* mono or grayscale, 0 is white
> */
> @@ -163,7 +171,7 @@ enum TiffPhotometric {
>      TIFF_PHOTOMETRIC_CIE_LAB    = 8,     /* 1976 CIE L*a*b* */
>      TIFF_PHOTOMETRIC_ICC_LAB,            /* ICC L*a*b* */
>      TIFF_PHOTOMETRIC_ITU_LAB,            /* ITU L*a*b* */
> -    TIFF_PHOTOMETRIC_CFA        = 32803, /* Color Filter Array (DNG) */
> +    TIFF_PHOTOMETRIC_CFA        = 32803, /* Color Filter Array (TIFF/AP and
> DNG) */
>      TIFF_PHOTOMETRIC_LOG_L      = 32844, /* CIE Log2(L) */
>      TIFF_PHOTOMETRIC_LOG_LUV,            /* CIE Log L*u*v* */
>      TIFF_PHOTOMETRIC_LINEAR_RAW = 34892, /* Linear Raw (DNG) */
> diff --git a/libavformat/img2.c b/libavformat/img2.c
> index 8432cc0955..16bc9d2abd 100644
> --- a/libavformat/img2.c
> +++ b/libavformat/img2.c
> @@ -51,6 +51,7 @@ const IdStrMap ff_img_tags[] = {
>      { AV_CODEC_ID_TARGA,      "tga"      },
>      { AV_CODEC_ID_TIFF,       "tiff"     },
>      { AV_CODEC_ID_TIFF,       "tif"      },
> +    { AV_CODEC_ID_TIFF,       "dng"      },
>      { AV_CODEC_ID_SGI,        "sgi"      },
>      { AV_CODEC_ID_PTX,        "ptx"      },
>      { AV_CODEC_ID_PCX,        "pcx"      },
> --
> 2.17.1.windows.2

Still wrong, There are DNG images without thumbnails.