tencent cloud

// 纯音频模式下，主实例（人声实例）需要开启补黑帧以携带 SEI 消息
NSDictionary *jsonDic = @{
                            @"api": @"enableBlackStream",
                            @"params": 
                                 @{
                                    @"enable": @(1)
                                  }
                          };
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonDic options:NSJSONWritingPrettyPrinted error:nil];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
[trtcCloud callExperimentalAPI:jsonString];

TXAudioMusicProgressBlock progressBlock = ^(NSInteger progressMs, NSInteger durationMs) {
    //当前 ntp 时间
    NSInteger ntpTime = [TXLiveBase getNetworkTimestamp];
    //通知歌曲进度，用户会在这里进行歌词的滚动
    NSDictionary *progressMsg = @{
            @"bgmProgressTime":@(progressMs),
            @"ntpTime":@(ntpTime),
            @"musicId": @(musicId),
            @"duration": @(durationMs),
    };
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:progressMsg options:NSJSONWritingPrettyPrinted error:nil];
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    [trtcCloud sendSEIMsg:[jsonString dataUsingEncoding:NSUTF8StringEncoding] repeatCount:1];
};

// 本地歌词同步
TXAudioMusicProgressBlock progressBlock = ^(NSInteger progressMs, NSInteger durationMs) {
    ...
    // TODO 更新歌词控件逻辑：
    // 根据最新进度和本地歌词进度误差，判断是否需要 seek 歌词控件
    ...
};

// 远端歌词同步
- (void)onRecvSEIMsg:(NSString *)userId message:(NSData *)message {
    NSError *err = nil;
    NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:message options:NSJSONReadingMutableContainers error:&err];
    if (err || ![dic isKindOfClass:[NSDictionary class]]) {
        // 解析出错
        return;
    }
    NSInteger bgmProgressTime = [[dic objectForKey:@"bgmProgressTime"] integerValue];
    NSInteger ntpTime = [[dic objectForKey:@"ntpTime"] integerValue];
    int32_t musicId = [[dic objectForKey:@"musicId"] intValue];
    NSInteger duration = [[dic objectForKey:@"duration"] integerValue];
    ...
    // TODO 更新歌词控件逻辑：
    // 根据接收到的最新进度和本地歌词进度误差，判断是否需要 seek 歌词控件
    ...
}