diff --git a/build/linux/unbundle/ffmpeg.gn b/build/linux/unbundle/ffmpeg.gn

index 16e20744706..6a079b32221 100644

--- a/build/linux/unbundle/ffmpeg.gn

+++ b/build/linux/unbundle/ffmpeg.gn

@@ -12,6 +12,7 @@ pkg_config("system_ffmpeg") {

     "libavformat",

     "libavutil",

   ]

+  defines = [ "av_stream_get_first_dts(stream)=stream->first_dts" ]

 }

 buildflag_header("ffmpeg_features") {

​