[FFmpeg-devel] [PATCH v4 1/4] avcodec: Add new side data type to contain original PTS value

[Devin Heitmueller]

In order to properly process SCTE-35 packets, we need the original
PTS value from the demux (i.e. not mangled by the application or
reclocked for the output).  This allows us to set the pts_adjustment
field in an BSF on the output side.

Introduce a new side data type to store the original PTS.

Signed-off-by: Devin Heitmueller <dheitmueller at ltnglobal.com>
---
 libavcodec/defs.h   | 12 ++++++++++++
 libavcodec/packet.h | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/libavcodec/defs.h b/libavcodec/defs.h
index fbe3254..ff50d25 100644
--- a/libavcodec/defs.h
+++ b/libavcodec/defs.h
@@ -28,6 +28,7 @@
 
 #include <stdint.h>
 #include <stdlib.h>
+#include "libavutil/rational.h"
 
 /**
  * @ingroup lavc_decoding
@@ -119,6 +120,17 @@ typedef struct AVPanScan {
 } AVPanScan;
 
 /**
+ * Original Transport Timestamp.  Provides the original timestamp
+ * of the packet as specified by the libavformat source  This allows that
+ * data to be used in calculations even if the clocks have been
+ * rebased or otherwise modified.
+ */
+typedef struct AVTransportTimestamp {
+    int64_t pts;
+    AVRational time_base;
+} AVTransportTimestamp;
+
+/**
  * This structure describes the bitrate properties of an encoded bitstream. It
  * roughly corresponds to a subset the VBV parameters for MPEG-2 or HRD
  * parameters for H.264/HEVC.
diff --git a/libavcodec/packet.h b/libavcodec/packet.h
index f28e7e7..8b650a8 100644
--- a/libavcodec/packet.h
+++ b/libavcodec/packet.h
@@ -300,6 +300,17 @@ enum AVPacketSideDataType {
     AV_PKT_DATA_DYNAMIC_HDR10_PLUS,
 
     /**
+     * Provides the original PTS when passed through the demux.  This can
+     * be used to offset any subsequent changes made by the caller to
+     * adjust PTS values (such as pts_offset).  We need this for SCTE-35,
+     * since by the time the packets reach the output the PTS values have
+     * already been re-written, and we cannot calculate pre-roll values
+     * using the PTS values embedded in the packet content
+     * Format for this data can be found in AVTransportTimestamp struct
+     */
+    AV_PKT_DATA_TRANSPORT_TIMESTAMP,
+
+    /**
      * The number of side data types.
      * This is not part of the public API/ABI in the sense that it may
      * change when new side data types are added.
-- 
1.8.3.1