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

velocityra at gmail.com velocityra at gmail.com
Wed May 29 15:57:27 EEST 2019


From: Nick Renieris <velocityra at gmail.com>

In DNG images with the .tiff extension, it solves the issue where the
TIFF thumbnail in IFD 0 was incorrectly parsed (related confusion: [1]).
Embedded thumbnails for DNG images can still be decoded with the added
"-dng_thumb" option.

Maintains current support for CinemaDNG (at least the ones found
in the wild) by detecting them and not erroring out in that case.

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 at gmail.com>
---
 libavcodec/tiff.c  | 48 +++++++++++++++++++++++++++++++++++++++++++++-
 libavcodec/tiff.h  | 36 +++++++++++++++++++++++++++++-----
 libavformat/img2.c |  1 +
 3 files changed, 79 insertions(+), 6 deletions(-)

diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 79e6242549..23d979eada 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -56,7 +56,9 @@ typedef struct TiffContext {
 
     int get_subimage;
     uint16_t get_page;
+    int get_dng_thumb;
 
+    enum TiffType tiff_type;
     int width, height;
     unsigned int bpp, bppcount;
     uint32_t palette[256];
@@ -70,6 +72,7 @@ typedef struct TiffContext {
     int predictor;
     int fill_order;
     uint32_t res[4];
+    int is_thumbnail;
 
     int is_bayer;
     uint8_t pattern[4];
@@ -94,6 +97,11 @@ typedef struct TiffContext {
     TiffGeoTag *geotags;
 } TiffContext;
 
+static void tiff_set_type(TiffContext *s, enum TiffType tiff_type) {
+    if (s->tiff_type < tiff_type) // Prioritize higher-valued entries
+        s->tiff_type = tiff_type;
+}
+
 static void free_geotags(TiffContext *const s)
 {
     int i;
@@ -948,6 +956,8 @@ static int tiff_decode_tag(TiffContext *s, AVFrame *frame)
     }
 
     switch (tag) {
+    case TIFF_SUBFILE:
+        s->is_thumbnail = (value != 0);
     case TIFF_WIDTH:
         s->width = value;
         break;
@@ -1088,7 +1098,7 @@ 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:
@@ -1339,6 +1349,27 @@ 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]);
+
+            tiff_set_type(s, TIFF_TYPE_DNG);
+        }
+        break;
+    case CINEMADNG_TIME_CODES:
+    case CINEMADNG_FRAME_RATE:
+    case CINEMADNG_T_STOP:
+    case CINEMADNG_REEL_NAME:
+    case CINEMADNG_CAMERA_LABEL:
+        tiff_set_type(s, TIFF_TYPE_CINEMADNG);
+        break;
     default:
         if (s->avctx->err_recognition & AV_EF_EXPLODE) {
             av_log(s->avctx, AV_LOG_ERROR,
@@ -1387,6 +1418,7 @@ static int decode_frame(AVCodecContext *avctx,
     s->le          = le;
     // TIFF_BPP is not a required tag and defaults to 1
 again:
+    s->is_thumbnail = 0;
     s->bppcount    = s->bpp = 1;
     s->photometric = TIFF_PHOTOMETRIC_NONE;
     s->compr       = TIFF_RAW;
@@ -1394,6 +1426,7 @@ again:
     s->white_level = 0;
     s->is_bayer    = 0;
     s->cur_page    = 0;
+    s->tiff_type   = TIFF_TYPE_TIFF;
     free_geotags(s);
 
     // Reset these offsets so we can tell if they were set this frame
@@ -1408,6 +1441,18 @@ again:
             return ret;
     }
 
+    if (s->tiff_type == TIFF_TYPE_DNG) {
+        if (!s->get_dng_thumb) {
+            av_log(avctx, AV_LOG_ERROR, "DNG images are not supported\n");
+            av_log(avctx, AV_LOG_INFO, "You can use -dng_thumb to decode an embedded TIFF thumbnail (if any) instead\n");
+            return AVERROR_INVALIDDATA;
+        }
+        if (!s->is_thumbnail) {
+            av_log(avctx, AV_LOG_INFO, "No embedded thumbnail present\n");
+            return AVERROR_EOF;
+        }
+    }
+
     /** whether we should look for this IFD's SubIFD */
     retry_for_subifd = s->sub_ifd && s->get_subimage;
     /** whether we should look for this multi-page IFD's next page */
@@ -1671,6 +1716,7 @@ static av_cold int tiff_end(AVCodecContext *avctx)
 static const AVOption tiff_options[] = {
     { "subimage", "decode subimage instead if available", OFFSET(get_subimage), AV_OPT_TYPE_BOOL, {.i64=0},  0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM },
     { "page", "page number of multi-page image to decode (starting from 1)", OFFSET(get_page), AV_OPT_TYPE_INT, {.i64=0}, 0, UINT16_MAX, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM },
+    { "dng_thumb", "decode TIFF thumbnail of DNG image", OFFSET(get_dng_thumb), AV_OPT_TYPE_BOOL, {.i64=0},  0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM },
     { NULL },
 };
 
diff --git a/libavcodec/tiff.h b/libavcodec/tiff.h
index 4b08650108..81913c6b1a 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 +33,17 @@
 #include <stdint.h>
 #include "tiff_common.h"
 
-/** abridged list of TIFF tags */
+/** TIFF types in ascenting priority (last in the list is highest) */
+enum TiffType {
+    /** TIFF image based on the TIFF 6.0 or TIFF/EP (ISO 12234-2) specifications */
+    TIFF_TYPE_TIFF,
+    /** Digital Negative (DNG) image */
+    TIFF_TYPE_DNG,
+    /** Digital Negative (DNG) image part of an CinemaDNG image sequence */
+    TIFF_TYPE_CINEMADNG,
+};
+
+/** abridged list of TIFF and TIFF/EP tags */
 enum TiffTags {
     TIFF_SUBFILE            = 0xfe,
     TIFF_WIDTH              = 0x100,
@@ -85,10 +95,25 @@ 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 CinemaDNG tags */
+enum CinemaDngTags {
+    CINEMADNG_TIME_CODES    = 0xC763,
+    CINEMADNG_FRAME_RATE    = 0xC764,
+    CINEMADNG_T_STOP        = 0xC772,
+    CINEMADNG_REEL_NAME     = 0xC789,
+    CINEMADNG_CAMERA_LABEL  = 0xC7A1,
+};
+
+/** list of TIFF, TIFF/EP and DNG compression types */
 enum TiffCompr {
     TIFF_RAW = 1,
     TIFF_CCITT_RLE,
@@ -151,6 +176,7 @@ 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 +189,7 @@ 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"      },
-- 
2.21.0.windows.1



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