From 9a0fbbe8461f70418881a807508bc9ca2aa0ffad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89lo=C3=AFse=20Brosseau?= <eloise.brosseau@autodesk.com>
Date: Mon, 18 Nov 2024 10:35:56 -0500
Subject: [PATCH] Add evStartFrameAtOne to enable the old behaviour if
 necessary
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Signed-off-by: Éloïse Brosseau <eloise.brosseau@autodesk.com>
---
 src/lib/image/MovieFFMpeg/MovieFFMpeg.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/lib/image/MovieFFMpeg/MovieFFMpeg.cpp b/src/lib/image/MovieFFMpeg/MovieFFMpeg.cpp
index 4f4156fb2..3239d99d7 100644
--- a/src/lib/image/MovieFFMpeg/MovieFFMpeg.cpp
+++ b/src/lib/image/MovieFFMpeg/MovieFFMpeg.cpp
@@ -52,7 +52,10 @@ extern "C" {
 //#include <libavcodec/ass_split.h>
 }
 
-static ENVVAR_BOOL( evUseUploadedMovieForStreaming, "RV_SHOTGRID_USE_UPLOADED_MOVIE_FOR_STREAMING", false );
+namespace {
+    ENVVAR_BOOL( evUseUploadedMovieForStreaming, "RV_SHOTGRID_USE_UPLOADED_MOVIE_FOR_STREAMING", false );
+    ENVVAR_BOOL(evStartFrameAtOne, "RV_START_FRAME_AT_ONE", false);
+}
 
 namespace TwkMovie {
 
@@ -1330,9 +1333,13 @@ MovieFFMpegReader::getFirstFrame(AVRational rate)
     // format start time, then we have to assume that the source's start is
     // offset by the given positive value.
     //
-
+    
     int64_t firstFrame = std::max(static_cast<int64_t>(0), static_cast<int64_t>(0.49 + av_q2d(rate) *
         static_cast<double>(m_avFormatContext->start_time) / static_cast<double>(AV_TIME_BASE)));
+    if (evStartFrameAtOne.getValue())
+    {
+        firstFrame = max(int64_t(m_formatStartFrame), int64_t(1));
+    }
 
     for (int i = 0; i < m_avFormatContext->nb_streams; i++)
     {