Fix up missing timestamps in FFmpegDemuxer.

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index 0c532d0edb1a84a026487497e29bdc7a5f10bb93..23de0e26c92d2ad9d604e251c3cbfff028248439 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -276,7 +276,8 @@ FFmpegDemuxerStream::FFmpegDemuxerStream(
       is_enabled_(true),
       waiting_for_keyframe_(false),
       aborted_(false),
-      fixup_negative_timestamps_(false) {
+      fixup_negative_timestamps_(false),
+      warned_about_missing_timestamps_(false) {
   DCHECK(demuxer_);
 
   bool is_encrypted = false;
@@ -527,7 +528,12 @@ void FFmpegDemuxerStream::EnqueuePacket(ScopedAVPacket packet) {
     }
   } else {
     // If this happens on the first packet, decoders will throw an error.
-    buffer->set_timestamp(kNoTimestamp);
+    // Just try zero.  crbug.com/665305 .
+    if (!warned_about_missing_timestamps_) {
+      LOG(WARNING) << "No timestamp provided for initial buffer";
+      warned_about_missing_timestamps_ = true;
+    }
+    buffer->set_timestamp(base::TimeDelta());
   }
 
   if (last_packet_timestamp_ != kNoTimestamp) {
@@ -544,18 +550,27 @@ void FFmpegDemuxerStream::EnqueuePacket(ScopedAVPacket packet) {
     // Fixing chained ogg is non-trivial, so for now just reuse the last good
     // timestamp.  The decoder will rewrite the timestamps to be sample accurate
     // later.  See http://crbug.com/396864.
-    if (fixup_negative_timestamps_ &&
-        (buffer->timestamp() == kNoTimestamp ||
+    //
+    // Whether we're fixing up timestamps or not, if we have no timestamp, then
+    // use the last timestamp instead.  This can happen if bad media causes
+    // ffmpeg to fail to provide a timestamp.  crbug.com/665305
+    if (buffer->timestamp() == kNoTimestamp ||
+        (fixup_negative_timestamps_ &&
          buffer->timestamp() < last_packet_timestamp_)) {
+      if (!fixup_negative_timestamps_ && !warned_about_missing_timestamps_) {

[liberato (no reviews please), 2016/12/12 22:24:48]

"!fixup..." to prevent a warning when we wouldn't have before.  no idea if we
actually care about this.

+        LOG(WARNING) << "No timestamp provided for buffer";
+        warned_about_missing_timestamps_ = true;
+      }
       buffer->set_timestamp(last_packet_timestamp_ +
                             (last_packet_duration_ != kNoTimestamp
                                  ? last_packet_duration_
                                  : base::TimeDelta::FromMicroseconds(1)));
     }
 
-    // The demuxer should always output positive timestamps.
-    DCHECK(buffer->timestamp() >= base::TimeDelta());
+    // The demuxer should always output non-negative timestamps.  If it output
+    // no timestamp, then we should have already fixed that up.
     DCHECK(buffer->timestamp() != kNoTimestamp);
+    DCHECK(buffer->timestamp() >= base::TimeDelta());
 
     if (last_packet_timestamp_ < buffer->timestamp()) {
       buffered_ranges_.Add(last_packet_timestamp_, buffer->timestamp());