Improving WebM video duration estimation.

media/base/stream_parser_buffer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/base/stream_parser_buffer.h"
 
 #include "base/logging.h"
 #include "media/base/buffers.h"
 
 namespace media {
 
 static scoped_refptr<StreamParserBuffer> CopyBuffer(
     const StreamParserBuffer& buffer) {
   if (buffer.end_of_stream())
     return StreamParserBuffer::CreateEOSBuffer();
 
   scoped_refptr<StreamParserBuffer> copied_buffer =
       StreamParserBuffer::CopyFrom(buffer.data(),
                                    buffer.data_size(),
                                    buffer.side_data(),
                                    buffer.side_data_size(),
                                    buffer.is_key_frame(),
                                    buffer.type(),
                                    buffer.track_id());
   copied_buffer->SetDecodeTimestamp(buffer.GetDecodeTimestamp());
   copied_buffer->SetConfigId(buffer.GetConfigId());
   copied_buffer->set_timestamp(buffer.timestamp());
   copied_buffer->set_duration(buffer.duration());
+  copied_buffer->set_is_duration_estimated(buffer.is_duration_estimated());
   copied_buffer->set_discard_padding(buffer.discard_padding());
   copied_buffer->set_splice_timestamp(buffer.splice_timestamp());
   const DecryptConfig* decrypt_config = buffer.decrypt_config();
   if (decrypt_config) {
     copied_buffer->set_decrypt_config(
         make_scoped_ptr(new DecryptConfig(decrypt_config->key_id(),
                                           decrypt_config->iv(),
                                           decrypt_config->subsamples())));
   }
 
@@ skipping 27 matching lines @@
     return DecodeTimestamp::FromPresentationTime(timestamp());
   return decode_timestamp_;
 }
 
 void StreamParserBuffer::SetDecodeTimestamp(DecodeTimestamp timestamp) {
   decode_timestamp_ = timestamp;
   if (preroll_buffer_.get())
     preroll_buffer_->SetDecodeTimestamp(timestamp);
 }
 
-StreamParserBuffer::StreamParserBuffer(const uint8* data, int data_size,
+StreamParserBuffer::StreamParserBuffer(const uint8* data,
+                                       int data_size,
                                        const uint8* side_data,
-                                       int side_data_size, bool is_key_frame,
-                                       Type type, TrackId track_id)
+                                       int side_data_size,
+                                       bool is_key_frame,
+                                       Type type,
+                                       TrackId track_id)
     : DecoderBuffer(data, data_size, side_data, side_data_size),
       decode_timestamp_(kNoDecodeTimestamp()),
       config_id_(kInvalidConfigId),
       type_(type),
-      track_id_(track_id) {
+      track_id_(track_id),
+      is_duration_estimated_(false) {
   // TODO(scherkus): Should DataBuffer constructor accept a timestamp and
   // duration to force clients to set them? Today they end up being zero which
   // is both a common and valid value and could lead to bugs.
   if (data) {
     set_duration(kNoTimestamp());
   }
 
   if (is_key_frame)
     set_is_key_frame(true);
 }
@@ skipping 47 matching lines @@
   }
 
   // Rewrite |this| buffer as a splice buffer.
   SetDecodeTimestamp(first_splice_buffer->GetDecodeTimestamp());
   SetConfigId(first_splice_buffer->GetConfigId());
   set_timestamp(first_splice_buffer->timestamp());
   set_is_key_frame(first_splice_buffer->is_key_frame());
   type_ = first_splice_buffer->type();
   track_id_ = first_splice_buffer->track_id();
   set_splice_timestamp(overlapping_buffer->timestamp());
 

[DaleCurtis, 2015/04/15 22:51:45]

Forward this new flag? Or DCHECK it's not present?

[chcunningham, 2015/04/16 18:04:16]

Done, added DCHECKs

   // The splice duration is the duration of all buffers before the splice plus
   // the highest ending timestamp after the splice point.
   DCHECK(overlapping_buffer->duration() > base::TimeDelta());
   DCHECK(pre_splice_buffers.back()->duration() > base::TimeDelta());
   set_duration(
       std::max(overlapping_buffer->timestamp() + overlapping_buffer->duration(),
                pre_splice_buffers.back()->timestamp() +
                    pre_splice_buffers.back()->duration()) -
       first_splice_buffer->timestamp());
 
@@ skipping 17 matching lines @@
   DCHECK(!preroll_buffer_.get());
   DCHECK(!end_of_stream());
   DCHECK(!preroll_buffer->end_of_stream());
   DCHECK(!preroll_buffer->preroll_buffer_.get());
   DCHECK(preroll_buffer->splice_timestamp() == kNoTimestamp());
   DCHECK(preroll_buffer->splice_buffers().empty());
   DCHECK(preroll_buffer->timestamp() <= timestamp());
   DCHECK(preroll_buffer->discard_padding() == DecoderBuffer::DiscardPadding());
   DCHECK_EQ(preroll_buffer->type(), type());
   DCHECK_EQ(preroll_buffer->track_id(), track_id());
 

[DaleCurtis, 2015/04/15 22:51:46]

Any DCHECKS() you want to add here?

[chcunningham, 2015/04/16 18:04:16]

I think estimation should be ok for pre-roll. Unlike splicing, pre-roll is not
expected to be overlapped. Also, I can imagine a webm stream that contains
estimated pre-roll, for which the estimation (and refinement in
SourceBufferStream) should work well just as it does in the non-preroll case. 

   preroll_buffer_ = preroll_buffer;
   preroll_buffer_->set_timestamp(timestamp());
   preroll_buffer_->SetDecodeTimestamp(GetDecodeTimestamp());
 
   // Mark the entire buffer for discard.
   preroll_buffer_->set_discard_padding(
       std::make_pair(kInfiniteDuration(), base::TimeDelta()));
 }
 
 void StreamParserBuffer::set_timestamp(base::TimeDelta timestamp) {
   DecoderBuffer::set_timestamp(timestamp);
   if (preroll_buffer_.get())
     preroll_buffer_->set_timestamp(timestamp);
 }
 
 }  // namespace media