From 440adb30868e686d279560fc73e8df4055e69cc6 Mon Sep 17 00:00:00 2001
From: Aaron Vaage <vaage@google.com>
Date: Thu, 7 Jun 2018 13:25:47 -0700
Subject: [PATCH] Remove Text Time Scale Assumption From Cue Alignment

In the cue aligner, we assumed that all text will be in milliseconds.
This was the last place with that assumption. This change removes that
assumption and uses the stream info's time scale.

Issue #399

Change-Id: Ie21bf27148e020bd85111dcace0bbdff3419c1ac
---
 .../media/chunking/cue_alignment_handler.cc   | 58 +++++++++----------
 1 file changed, 28 insertions(+), 30 deletions(-)

diff --git a/packager/media/chunking/cue_alignment_handler.cc b/packager/media/chunking/cue_alignment_handler.cc
index f209e869d9..6588852e12 100644
--- a/packager/media/chunking/cue_alignment_handler.cc
+++ b/packager/media/chunking/cue_alignment_handler.cc
@@ -16,38 +16,36 @@ namespace {
 // configured. This is about 20 seconds of buffer for audio with 48kHz.
 const size_t kMaxBufferSize = 1000;
 
-double TimeInSeconds(const StreamInfo& info, const StreamData& data) {
-  int64_t time_scale;
-  int64_t scaled_time;
-  switch (data.stream_data_type) {
-    case StreamDataType::kMediaSample:
-      time_scale = info.time_scale();
-      if (info.stream_type() == kStreamAudio) {
-        // Return the start time for video and mid-point for audio, so that for
-        // an audio sample, if the portion of the sample after the cue point is
-        // bigger than the portion of the sample before the cue point, the
-        // sample is placed after the cue.
-        // It does not matter for text samples as text samples will be cut at
-        // cue point.
-        scaled_time =
-            data.media_sample->pts() + data.media_sample->duration() / 2;
-      } else {
-        scaled_time = data.media_sample->pts();
-      }
-      break;
-    case StreamDataType::kTextSample:
-      // Text is always in MS but the stream info time scale is 0.
-      time_scale = 1000;
-      scaled_time = data.text_sample->start_time();
-      break;
-    default:
-      time_scale = 0;
-      scaled_time = 0;
-      NOTREACHED() << "TimeInSeconds should only be called on media samples "
-                      "and text samples.";
-      break;
+int64_t GetScaledTime(const StreamInfo& info, const StreamData& data) {
+  DCHECK(data.text_sample || data.media_sample);
+
+  if (data.text_sample) {
+    return data.text_sample->start_time();
   }
 
+  if (info.stream_type() == kStreamText) {
+    // This class does not support splitting MediaSample at cue points, which is
+    // required for text stream. This class expects MediaSample to be converted
+    // to TextSample before passing to this class.
+    NOTREACHED()
+        << "A text streams should use text samples, not media samples.";
+  }
+
+  if (info.stream_type() == kStreamAudio) {
+    // Return the mid-point for audio because if the portion of the sample
+    // after the cue point is bigger than the portion of the sample before
+    // the cue point, the sample is placed after the cue.
+    return data.media_sample->pts() + data.media_sample->duration() / 2;
+  }
+
+  DCHECK_EQ(info.stream_type(), kStreamVideo);
+  return data.media_sample->pts();
+}
+
+double TimeInSeconds(const StreamInfo& info, const StreamData& data) {
+  const int64_t scaled_time = GetScaledTime(info, data);
+  const uint32_t time_scale = info.time_scale();
+
   return static_cast<double>(scaled_time) / time_scale;
 }