1/*
2 * Copyright (C) 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17import {ArrayUtils} from 'common/array_utils';
18import {Timestamp} from 'common/time';
19import {AbstractParser} from 'parsers/legacy/abstract_parser';
20import {MediaBasedTraceEntry} from 'trace/media_based_trace_entry';
21import {ScreenRecordingUtils} from 'trace/screen_recording_utils';
22import {TraceType} from 'trace/trace_type';
23
24class ParserScreenRecordingLegacy extends AbstractParser {
25  override getTraceType(): TraceType {
26    return TraceType.SCREEN_RECORDING;
27  }
28
29  override getMagicNumber(): number[] {
30    return ParserScreenRecordingLegacy.MPEG4_MAGIC_NUMBER;
31  }
32
33  override getRealToMonotonicTimeOffsetNs(): bigint | undefined {
34    return undefined;
35  }
36
37  override getRealToBootTimeOffsetNs(): bigint | undefined {
38    return undefined;
39  }
40
41  override decodeTrace(videoData: Uint8Array): Array<bigint> {
42    const posCount = this.searchMagicString(videoData);
43    const [posTimestamps, count] = this.parseFramesCount(videoData, posCount);
44    return this.parseVideoData(videoData, posTimestamps, count);
45  }
46
47  protected override getTimestamp(decodedEntry: bigint): Timestamp {
48    return this.timestampConverter.makeTimestampFromMonotonicNs(decodedEntry);
49  }
50
51  override processDecodedEntry(
52    index: number,
53    entry: bigint,
54  ): MediaBasedTraceEntry {
55    const videoTimeSeconds = ScreenRecordingUtils.timestampToVideoTimeSeconds(
56      this.decodedEntries[0],
57      entry,
58    );
59    const videoData = this.traceFile.file;
60    return new MediaBasedTraceEntry(videoTimeSeconds, videoData);
61  }
62
63  private searchMagicString(videoData: Uint8Array): number {
64    let pos = ArrayUtils.searchSubarray(
65      videoData,
66      ParserScreenRecordingLegacy.WINSCOPE_META_MAGIC_STRING,
67    );
68    if (pos === undefined) {
69      throw new TypeError("video data doesn't contain winscope magic string");
70    }
71    pos += ParserScreenRecordingLegacy.WINSCOPE_META_MAGIC_STRING.length;
72    return pos;
73  }
74
75  private parseFramesCount(
76    videoData: Uint8Array,
77    pos: number,
78  ): [number, number] {
79    if (pos + 4 > videoData.length) {
80      throw new TypeError(
81        'Failed to parse frames count. Video data is too short.',
82      );
83    }
84    const framesCount = Number(
85      ArrayUtils.toUintLittleEndian(videoData, pos, pos + 4),
86    );
87    pos += 4;
88    return [pos, framesCount];
89  }
90
91  private parseVideoData(
92    videoData: Uint8Array,
93    pos: number,
94    count: number,
95  ): Array<bigint> {
96    if (pos + count * 8 > videoData.length) {
97      throw new TypeError(
98        'Failed to parse timestamps. Video data is too short.',
99      );
100    }
101    const timestamps: Array<bigint> = [];
102    for (let i = 0; i < count; ++i) {
103      const value =
104        ArrayUtils.toUintLittleEndian(videoData, pos, pos + 8) * 1000n;
105      pos += 8;
106      timestamps.push(value);
107    }
108    return timestamps;
109  }
110
111  private static readonly MPEG4_MAGIC_NUMBER = [
112    0x00, 0x00, 0x00, 0x18, 0x66, 0x74, 0x79, 0x70, 0x6d, 0x70, 0x34, 0x32,
113  ]; // ....ftypmp42
114  private static readonly WINSCOPE_META_MAGIC_STRING = [
115    0x23, 0x56, 0x56, 0x31, 0x4e, 0x53, 0x43, 0x30, 0x50, 0x45, 0x54, 0x31,
116    0x4d, 0x45, 0x21, 0x23,
117  ]; // #VV1NSC0PET1ME!#
118  private static readonly EPSILON = 0.00001;
119}
120
121export {ParserScreenRecordingLegacy};
122