[FFmpeg-devel] [PATCH] libavformat/mov: Add support for exporting poster time.

* [FFmpeg-devel] [PATCH] libavformat/mov: Add support for exporting poster time.
@ 2022-10-03 16:08 Bryce Chester Newman
  2022-10-05 14:25 ` [FFmpeg-devel] [PATCH v2 0/2] " ffmpegagent
  0 siblings, 1 reply; 7+ messages in thread
From: Bryce Chester Newman @ 2022-10-03 16:08 UTC (permalink / raw)
  To: ffmpeg-devel; +Cc: Bryce Chester Newman

From: Bryce Chester Newman <bryce.newman@gettyimages.com>

Export the poster_time_location if available.
The poster_time_location is calculated using
the poster_time / time_scale = X seconds.
The value of poster_time_location indicates
where in the video the poster frame is.

Addresses feedback
from https://www.mail-archive.com/ffmpeg-devel@ffmpeg.org/msg138122.html.

Signed-off-by: Bryce Chester Newman bryce.newman@gettyimages.com
---
    libavformat/mov: Add support for exporting poster time.
    
    Export the poster_time_location if available. The poster_time_location
    is calculated using the poster_time / time_scale = X seconds. The value
    of poster_time_location indicates where in the video the poster frame
    is.
    
    Addresses feedback from
    https://www.mail-archive.com/ffmpeg-devel@ffmpeg.org/msg138122.html.
    
    Signed-off-by: Bryce Chester Newman bryce.newman@gettyimages.com

Published-As: https://github.com/ffstaging/FFmpeg/releases/tag/pr-ffstaging-41%2Fbrycechesternewman%2Fadd_poster_time_location_mov-v1
Fetch-It-Via: git fetch https://github.com/ffstaging/FFmpeg pr-ffstaging-41/brycechesternewman/add_poster_time_location_mov-v1
Pull-Request: https://github.com/ffstaging/FFmpeg/pull/41

 doc/demuxers.texi  |  6 ++++++
 libavformat/isom.h |  1 +
 libavformat/mov.c  | 13 +++++++++++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/doc/demuxers.texi b/doc/demuxers.texi
index 2b6dd86c2a..b1f4926c40 100644
--- a/doc/demuxers.texi
+++ b/doc/demuxers.texi
@@ -749,6 +749,12 @@ cast to int32 are used to adjust onward dts.
 
 Unit is the track time scale. Range is 0 to UINT_MAX. Default is @code{UINT_MAX - 48000*10} which allows upto
 a 10 second dts correction for 48 kHz audio streams while accommodating 99.9% of @code{uint32} range.
+
+@item poster_time_location
+Export the poster_time_location if available.
+The poster_time_location is calculated using the poster_time / time_scale = X seconds.
+The value of poster_time_location indicates where in the video the poster frame is.
+Default is false.
 @end table
 
 @subsection Audible AAX
diff --git a/libavformat/isom.h b/libavformat/isom.h
index 64fb7065d5..fb3d8d5618 100644
--- a/libavformat/isom.h
+++ b/libavformat/isom.h
@@ -326,6 +326,7 @@ typedef struct MOVContext {
         int64_t extent_offset;
     } *avif_info;
     int avif_info_size;
+    int poster_time_location;
 } MOVContext;
 
 int ff_mp4_read_descr_len(AVIOContext *pb);
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 1f436e21d6..b914bbc96a 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1501,6 +1501,7 @@ static int mov_read_mvhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     int i;
     int64_t creation_time;
+    int32_t poster_time;
     int version = avio_r8(pb); /* version */
     avio_rb24(pb); /* flags */
 
@@ -1535,12 +1536,20 @@ static int mov_read_mvhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     avio_rb32(pb); /* preview time */
     avio_rb32(pb); /* preview duration */
-    avio_rb32(pb); /* poster time */
+    poster_time = avio_rb32(pb); /* poster time */
     avio_rb32(pb); /* selection time */
     avio_rb32(pb); /* selection duration */
     avio_rb32(pb); /* current time */
     avio_rb32(pb); /* next track ID */
 
+    if(c->poster_time_location && poster_time && c->time_scale && c->time_scale > 0) {
+        av_log(c->fc, AV_LOG_TRACE, "poster_time = %i, time_scale = %i\n", poster_time, c->time_scale);
+        char buffer[32];
+        int poster_time_location = poster_time / c->time_scale;
+        snprintf(buffer, sizeof(buffer), "%i", poster_time_location);
+        av_dict_set(&c->fc->metadata, "poster_time_location", buffer, 0);
+    }
+
     return 0;
 }
 
@@ -9114,7 +9123,7 @@ static const AVOption mov_options[] = {
     { "enable_drefs", "Enable external track support.", OFFSET(enable_drefs), AV_OPT_TYPE_BOOL,
         {.i64 = 0}, 0, 1, FLAGS },
     { "max_stts_delta", "treat offsets above this value as invalid", OFFSET(max_stts_delta), AV_OPT_TYPE_INT, {.i64 = UINT_MAX-48000*10 }, 0, UINT_MAX, .flags = AV_OPT_FLAG_DECODING_PARAM },
-
+    { "poster_time_location", "Export the poster time location.", OFFSET(poster_time_location), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS | AV_OPT_FLAG_EXPORT },
     { NULL },
 };
 

base-commit: 5f02a261a2ddca7c79198869b45d35019baac819
-- 
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