blob: 665501c320ee34534ecf4834ff8098f45f994efc (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
|
// Copyright 2016 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.
#ifndef MEDIA_FILTERS_AUDIO_TIMESTAMP_VALIDATOR_H_
#define MEDIA_FILTERS_AUDIO_TIMESTAMP_VALIDATOR_H_
#include "base/memory/ref_counted.h"
#include "base/time/time.h"
#include "media/base/audio_buffer.h"
#include "media/base/audio_decoder_config.h"
#include "media/base/audio_timestamp_helper.h"
#include "media/base/decoder_buffer.h"
#include "media/base/media_log.h"
#include "media/base/timestamp_constants.h"
namespace media {
class MEDIA_EXPORT AudioTimestampValidator {
public:
AudioTimestampValidator(const AudioDecoderConfig& decoder_config,
MediaLog* media_log);
~AudioTimestampValidator();
// These methods monitor DecoderBuffer timestamps for gaps for the purpose of
// warning developers when gaps may cause AV sync drift. A DecoderBuffer's
// timestamp should roughly equal the timestamp of the previous buffer offset
// by the previous buffer's duration.
void CheckForTimestampGap(const DecoderBuffer& buffer);
void RecordOutputDuration(const scoped_refptr<AudioBuffer>& buffer);
private:
bool has_codec_delay_;
MediaLog* media_log_;
// Accumulates time from decoded audio frames. We adjust the base timestamp as
// needed for the first few buffers (stabilization period) of decoded output
// to account for pre-skip and codec delay. See CheckForTimestampGap().
std::unique_ptr<AudioTimestampHelper> audio_output_ts_helper_;
base::TimeDelta audio_base_ts_;
// Initially false, set to true when we observe gap between encoded timestamps
// match gap between output decoder buffers.
bool reached_stable_state_;
// Counts attempts to adjust |audio_output_ts_helper_| base offset in effort
// to form expectation for encoded timestamps based on decoded output. Give up
// making adjustments when count exceeds |limit_unstable_audio_tries_|.
int num_unstable_audio_tries_;
// Limits the number of attempts to stabilize audio timestamp expectations.
int limit_unstable_audio_tries_;
// How many milliseconds can DecoderBuffer timestamps differ from expectations
// before we MEDIA_LOG warn developers. Threshold initially set from
// kGapWarningThresholdMsec. Once hit, the threshold is increased by
// the detected gap amount. This avoids log spam while still emitting
// logs if things get worse. See CheckTimestampForGap().
uint32_t drift_warning_threshold_msec_;
// Tracks the number of MEDIA_LOG warnings when large timestamp gap detected.
int num_timestamp_gap_warnings_ = 0;
DISALLOW_COPY_AND_ASSIGN(AudioTimestampValidator);
};
} // namespace media
#endif // MEDIA_FILTERS_AUDIO_TIMESTAMP_VALIDATOR_H_
|
