2. 程式人生 > 實用技巧 >FFMPEG Tips (3) 如何讀取每一幀的資訊

FFMPEG Tips (3) 如何讀取每一幀的資訊

阿新 • • 發佈：2020-09-06

1. 碼流中每一幀的哪些資訊值得關注 ？

[ ] 音訊幀還是視訊幀

[ ] 關鍵幀還是非關鍵幀

[ ] 幀的資料和大小

[ ] 時間戳資訊

2. 為什麼要關注這些資訊 ？

[ ] 音訊幀還是視訊幀 -> 分別送入音訊/視訊×××

[ ] 關鍵幀還是非關鍵幀 -> 追幀優化

[ ] 幀的資料和大小 -> 取出幀的內容

[ ] 時間戳資訊 -> 音視訊同步

3. 如何從 ffmpeg 取出這些資訊 ？

ffmpeg 提供了一個函式 av_read_frame 來完成解封裝的過程，它會從碼流裡面提取每一個音訊、視訊幀，它使用了結構體 AVPacket 來記錄每一幀的資訊。

讀取一幀資料的程式碼示例如下（ic 即為 AVFormatContext 物件，碼流的上下文控制代碼）：

AVPacket avpkt;
av_init_packet(&avpkt);

while (!interrupt) {
    int ret = av_read_frame(ic, &avpkt);
    if (ret < 0) {
        break;
    }
    // processing
}

av_free_packet(&avpkt);

每迴圈一次，就從碼流中解封裝並且提取了一幀資料，並存放在了 AVPacket 結構體中。

3.1 如何判斷是音訊幀還是視訊幀

上一篇文章我們提到過，使用下面的方法，獲取碼流中的 video_stream_idx 和 audio_stream_idx

int video_stream_idx = av_find_best_stream(ic, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);

int audio_stream_idx = av_find_best_stream(ic, AVMEDIA_TYPE_AUDIO, -1, -1, NULL, 0);

那麼，此時就派上用場了，每一個 AVPacket 都有一個成員變數：stream_index，由該成員變數即可判斷這個 Packet 到底是音訊還是視訊了：

if (avpkt.stream_index == video_stream_idx) {
    LOGD("read a video frame");
} else if (avpkt.stream_index == audio_stream_idx) {
    LOGD("read audio frame);
}

3.2 如何判斷是否為關鍵幀

判斷是否為關鍵幀的方法也比較簡單，示例如下：

if (avpkt.flags & AV_PKT_FLAG_KEY) {
    LOGD("read a key frame");
}

3.3 如何獲取幀的資料和大小

幀的資料和大小直接定義在 AVPacket 結構體中，對應的成員變數如下：

// 壓縮編碼的資料，一幀音訊/視訊
uint8_t *data;

// 資料的大小
int size;

www.imdb.com/list/ls083027164/
www.imdb.com/list/ls083027164/?ref_=otl_Z
m.imdb.com/list/ls083027164/
www.imdb.com/list/ls083027164/?ref_=otl_5x
www.imdb.com/list/ls083027164/?ref_=otl_7
www.imdb.com/list/ls083027164/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027164/?fjxzl=5x
www.imdb.com/list/ls083027164/?mode=desktop
www.imdb.com/list/ls083027128/
www.imdb.com/list/ls083027128/?ref_=otl_K
m.imdb.com/list/ls083027128/
www.imdb.com/list/ls083027128/?ref_=otl_e6
www.imdb.com/list/ls083027128/?ref_=otl_0
www.imdb.com/list/ls083027128/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027128/?kywkw=e6
www.imdb.com/list/ls083027128/?mode=desktop
www.imdb.com/list/ls083027143/
www.imdb.com/list/ls083027143/?ref_=otl_z
m.imdb.com/list/ls083027143/
www.imdb.com/list/ls083027143/?ref_=otl_FJ
www.imdb.com/list/ls083027143/?ref_=otl_6
www.imdb.com/list/ls083027143/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027143/?kueef=FJ
www.imdb.com/list/ls083027143/?mode=desktop
www.imdb.com/list/ls083027199/
www.imdb.com/list/ls083027199/?ref_=otl_7
m.imdb.com/list/ls083027199/
www.imdb.com/list/ls083027199/?ref_=otl_X3
www.imdb.com/list/ls083027199/?ref_=otl_5
www.imdb.com/list/ls083027199/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027199/?btnrd=X3
www.imdb.com/list/ls083027199/?mode=desktop
www.imdb.com/list/ls083027184/
www.imdb.com/list/ls083027184/?ref_=otl_F
m.imdb.com/list/ls083027184/
www.imdb.com/list/ls083027184/?ref_=otl_R1
www.imdb.com/list/ls083027184/?ref_=otl_7
www.imdb.com/list/ls083027184/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027184/?znnnr=R1
www.imdb.com/list/ls083027184/?mode=desktop
www.imdb.com/list/ls083027304/
www.imdb.com/list/ls083027304/?ref_=otl_u
m.imdb.com/list/ls083027304/
www.imdb.com/list/ls083027304/?ref_=otl_Sg
www.imdb.com/list/ls083027304/?ref_=otl_8
www.imdb.com/list/ls083027304/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027304/?kyyco=Sg
www.imdb.com/list/ls083027304/?mode=desktop
www.imdb.com/list/ls083027357/
www.imdb.com/list/ls083027357/?ref_=otl_P
m.imdb.com/list/ls083027357/
www.imdb.com/list/ls083027357/?ref_=otl_zt
www.imdb.com/list/ls083027357/?ref_=otl_5
www.imdb.com/list/ls083027357/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027357/?lpxld=zt
www.imdb.com/list/ls083027357/?mode=desktop
www.imdb.com/list/ls083027371/
www.imdb.com/list/ls083027371/?ref_=otl_g
m.imdb.com/list/ls083027371/
www.imdb.com/list/ls083027371/?ref_=otl_cH
www.imdb.com/list/ls083027371/?ref_=otl_7
www.imdb.com/list/ls083027371/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027371/?mcrgg=cH
www.imdb.com/list/ls083027371/?mode=desktop
www.imdb.com/list/ls083027374/
www.imdb.com/list/ls083027374/?ref_=otl_l
m.imdb.com/list/ls083027374/
www.imdb.com/list/ls083027374/?ref_=otl_53
www.imdb.com/list/ls083027374/?ref_=otl_5
www.imdb.com/list/ls083027374/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027374/?lpnnp=53
www.imdb.com/list/ls083027374/?mode=desktop
www.imdb.com/list/ls083027313/
www.imdb.com/list/ls083027313/?ref_=otl_7
m.imdb.com/list/ls083027313/
www.imdb.com/list/ls083027313/?ref_=otl_x5
www.imdb.com/list/ls083027313/?ref_=otl_3
www.imdb.com/list/ls083027313/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027313/?vxxzz=x5
www.imdb.com/list/ls083027313/?mode=desktop
www.imdb.com/list/ls083027319/
www.imdb.com/list/ls083027319/?ref_=otl_C
m.imdb.com/list/ls083027319/
www.imdb.com/list/ls083027319/?ref_=otl_eC
www.imdb.com/list/ls083027319/?ref_=otl_4
www.imdb.com/list/ls083027319/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027319/?cecee=eC
www.imdb.com/list/ls083027319/?mode=desktop
www.imdb.com/list/ls083027339/
www.imdb.com/list/ls083027339/?ref_=otl_B
m.imdb.com/list/ls083027339/
www.imdb.com/list/ls083027339/?ref_=otl_fB
www.imdb.com/list/ls083027339/?ref_=otl_1
www.imdb.com/list/ls083027339/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027339/?ddbbd=fB
www.imdb.com/list/ls083027339/?mode=desktop
www.imdb.com/list/ls083027361/
www.imdb.com/list/ls083027361/?ref_=otl_O
m.imdb.com/list/ls083027361/
www.imdb.com/list/ls083027361/?ref_=otl_62
www.imdb.com/list/ls083027361/?ref_=otl_0
www.imdb.com/list/ls083027361/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027361/?oycss=62
www.imdb.com/list/ls083027361/?mode=desktop
www.imdb.com/list/ls083027326/
www.imdb.com/list/ls083027326/?ref_=otl_7
m.imdb.com/list/ls083027326/
www.imdb.com/list/ls083027326/?ref_=otl_Hn
www.imdb.com/list/ls083027326/?ref_=otl_5
www.imdb.com/list/ls083027326/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027326/?jrfbp=Hn
www.imdb.com/list/ls083027326/?mode=desktop
www.imdb.com/list/ls083027329/
www.imdb.com/list/ls083027329/?ref_=otl_x
m.imdb.com/list/ls083027329/
www.imdb.com/list/ls083027329/?ref_=otl_7T
www.imdb.com/list/ls083027329/?ref_=otl_3
www.imdb.com/list/ls083027329/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027329/?rphhh=7T
www.imdb.com/list/ls083027329/?mode=desktop
www.imdb.com/list/ls083027391/
www.imdb.com/list/ls083027391/?ref_=otl_2
m.imdb.com/list/ls083027391/
www.imdb.com/list/ls083027391/?ref_=otl_2W
www.imdb.com/list/ls083027391/?ref_=otl_6
www.imdb.com/list/ls083027391/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027391/?agcie=2W
www.imdb.com/list/ls083027391/?mode=desktop
www.imdb.com/list/ls083027399/
www.imdb.com/list/ls083027399/?ref_=otl_P
m.imdb.com/list/ls083027399/
www.imdb.com/list/ls083027399/?ref_=otl_95
www.imdb.com/list/ls083027399/?ref_=otl_9
www.imdb.com/list/ls083027399/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027399/?tpddz=95
www.imdb.com/list/ls083027399/?mode=desktop
www.imdb.com/list/ls083027384/
www.imdb.com/list/ls083027384/?ref_=otl_W
m.imdb.com/list/ls083027384/
www.imdb.com/list/ls083027384/?ref_=otl_W4
www.imdb.com/list/ls083027384/?ref_=otl_8
www.imdb.com/list/ls083027384/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027384/?skssy=W4
www.imdb.com/list/ls083027384/?mode=desktop
www.imdb.com/list/ls083027607/
www.imdb.com/list/ls083027607/?ref_=otl_p
m.imdb.com/list/ls083027607/
www.imdb.com/list/ls083027607/?ref_=otl_15
www.imdb.com/list/ls083027607/?ref_=otl_9
www.imdb.com/list/ls083027607/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027607/?jjxfj=15
www.imdb.com/list/ls083027607/?mode=desktop
www.imdb.com/list/ls083027651/
www.imdb.com/list/ls083027651/?ref_=otl_1
m.imdb.com/list/ls083027651/
www.imdb.com/list/ls083027651/?ref_=otl_82
www.imdb.com/list/ls083027651/?ref_=otl_8
www.imdb.com/list/ls083027651/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027651/?wvvwl=82
www.imdb.com/list/ls083027651/?mode=desktop
www.imdb.com/list/ls083027659/
www.imdb.com/list/ls083027659/?ref_=otl_8
m.imdb.com/list/ls083027659/
www.imdb.com/list/ls083027659/?ref_=otl_ai
www.imdb.com/list/ls083027659/?ref_=otl_2
www.imdb.com/list/ls083027659/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027659/?iayai=ai
www.imdb.com/list/ls083027659/?mode=desktop
www.imdb.com/list/ls083027679/
www.imdb.com/list/ls083027679/?ref_=otl_1
m.imdb.com/list/ls083027679/
www.imdb.com/list/ls083027679/?ref_=otl_37
www.imdb.com/list/ls083027679/?ref_=otl_7
www.imdb.com/list/ls083027679/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027679/?hlhlj=37
www.imdb.com/list/ls083027679/?mode=desktop
www.imdb.com/list/ls083027615/
www.imdb.com/list/ls083027615/?ref_=otl_5
m.imdb.com/list/ls083027615/
www.imdb.com/list/ls083027615/?ref_=otl_f8
www.imdb.com/list/ls083027615/?ref_=otl_9
www.imdb.com/list/ls083027615/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027615/?ppquu=f8
www.imdb.com/list/ls083027615/?mode=desktop
www.imdb.com/list/ls083027631/
www.imdb.com/list/ls083027631/?ref_=otl_C
m.imdb.com/list/ls083027631/
www.imdb.com/list/ls083027631/?ref_=otl_cg
www.imdb.com/list/ls083027631/?ref_=otl_8
www.imdb.com/list/ls083027631/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027631/?mwymq=cg
www.imdb.com/list/ls083027631/?mode=desktop
www.imdb.com/list/ls083027634/
www.imdb.com/list/ls083027634/?ref_=otl_M
m.imdb.com/list/ls083027634/
www.imdb.com/list/ls083027634/?ref_=otl_88
www.imdb.com/list/ls083027634/?ref_=otl_6
www.imdb.com/list/ls083027634/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027634/?eoekq=88
www.imdb.com/list/ls083027634/?mode=desktop
www.imdb.com/list/ls083027625/
www.imdb.com/list/ls083027625/?ref_=otl_0
m.imdb.com/list/ls083027625/
www.imdb.com/list/ls083027625/?ref_=otl_2w
www.imdb.com/list/ls083027625/?ref_=otl_6
www.imdb.com/list/ls083027625/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027625/?uyekm=2w
www.imdb.com/list/ls083027625/?mode=desktop
www.imdb.com/list/ls083027626/
www.imdb.com/list/ls083027626/?ref_=otl_7
m.imdb.com/list/ls083027626/
www.imdb.com/list/ls083027626/?ref_=otl_77
www.imdb.com/list/ls083027626/?ref_=otl_7
www.imdb.com/list/ls083027626/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027626/?zbzhf=77
www.imdb.com/list/ls083027626/?mode=desktop
www.imdb.com/list/ls083027648/
www.imdb.com/list/ls083027648/?ref_=otl_W
m.imdb.com/list/ls083027648/
www.imdb.com/list/ls083027648/?ref_=otl_uO
www.imdb.com/list/ls083027648/?ref_=otl_6
www.imdb.com/list/ls083027648/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027648/?uwwqk=uO
www.imdb.com/list/ls083027648/?mode=desktop
www.imdb.com/list/ls083027697/
www.imdb.com/list/ls083027697/?ref_=otl_a
m.imdb.com/list/ls083027697/
www.imdb.com/list/ls083027697/?ref_=otl_2y
www.imdb.com/list/ls083027697/?ref_=otl_4
www.imdb.com/list/ls083027697/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027697/?agykw=2y
www.imdb.com/list/ls083027697/?mode=desktop
www.imdb.com/list/ls083027687/
www.imdb.com/list/ls083027687/?ref_=otl_H
m.imdb.com/list/ls083027687/
www.imdb.com/list/ls083027687/?ref_=otl_3j
www.imdb.com/list/ls083027687/?ref_=otl_9
www.imdb.com/list/ls083027687/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027687/?hfzpb=3j
www.imdb.com/list/ls083027687/?mode=desktop
www.imdb.com/list/ls083027686/
www.imdb.com/list/ls083027686/?ref_=otl_O
m.imdb.com/list/ls083027686/
www.imdb.com/list/ls083027686/?ref_=otl_8s
www.imdb.com/list/ls083027686/?ref_=otl_4
www.imdb.com/list/ls083027686/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027686/?oasyu=8s
www.imdb.com/list/ls083027686/?mode=desktop
www.imdb.com/list/ls083027204/
www.imdb.com/list/ls083027204/?ref_=otl_5
m.imdb.com/list/ls083027204/
www.imdb.com/list/ls083027204/?ref_=otl_34
www.imdb.com/list/ls083027204/?ref_=otl_5
www.imdb.com/list/ls083027204/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027204/?gssor=34
www.imdb.com/list/ls083027204/?mode=desktop
www.imdb.com/list/ls083027208/
www.imdb.com/list/ls083027208/?ref_=otl_4
m.imdb.com/list/ls083027208/
www.imdb.com/list/ls083027208/?ref_=otl_WG
www.imdb.com/list/ls083027208/?ref_=otl_8
www.imdb.com/list/ls083027208/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027208/?oaqug=WG
www.imdb.com/list/ls083027208/?mode=desktop
www.imdb.com/list/ls083027275/
www.imdb.com/list/ls083027275/?ref_=otl_2
m.imdb.com/list/ls083027275/
www.imdb.com/list/ls083027275/?ref_=otl_Y6
www.imdb.com/list/ls083027275/?ref_=otl_4
www.imdb.com/list/ls083027275/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027275/?siokk=Y6
www.imdb.com/list/ls083027275/?mode=desktop
www.imdb.com/list/ls083027272/
www.imdb.com/list/ls083027272/?ref_=otl_1
m.imdb.com/list/ls083027272/
www.imdb.com/list/ls083027272/?ref_=otl_FB
www.imdb.com/list/ls083027272/?ref_=otl_7
www.imdb.com/list/ls083027272/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027272/?hxpdd=FB
www.imdb.com/list/ls083027272/?mode=desktop
www.imdb.com/list/ls083027216/
www.imdb.com/list/ls083027216/?ref_=otl_s
m.imdb.com/list/ls083027216/
www.imdb.com/list/ls083027216/?ref_=otl_8c
www.imdb.com/list/ls083027216/?ref_=otl_2
www.imdb.com/list/ls083027216/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027216/?sgwak=8c
www.imdb.com/list/ls083027216/?mode=desktop
www.imdb.com/list/ls083027235/
www.imdb.com/list/ls083027235/?ref_=otl_J
m.imdb.com/list/ls083027235/
www.imdb.com/list/ls083027235/?ref_=otl_XL
www.imdb.com/list/ls083027235/?ref_=otl_1
www.imdb.com/list/ls083027235/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027235/?vlltj=XL
www.imdb.com/list/ls083027235/?mode=desktop
www.imdb.com/list/ls083027238/
www.imdb.com/list/ls083027238/?ref_=otl_L
m.imdb.com/list/ls083027238/
www.imdb.com/list/ls083027238/?ref_=otl_3l
www.imdb.com/list/ls083027238/?ref_=otl_7
www.imdb.com/list/ls083027238/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027238/?xtzhj=3l
www.imdb.com/list/ls083027238/?mode=desktop
www.imdb.com/list/ls083027263/
www.imdb.com/list/ls083027263/?ref_=otl_E
m.imdb.com/list/ls083027263/
www.imdb.com/list/ls083027263/?ref_=otl_Y6
www.imdb.com/list/ls083027263/?ref_=otl_0
www.imdb.com/list/ls083027263/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027263/?mqawo=Y6
www.imdb.com/list/ls083027263/?mode=desktop
www.imdb.com/list/ls083027225/
www.imdb.com/list/ls083027225/?ref_=otl_4
m.imdb.com/list/ls083027225/
www.imdb.com/list/ls083027225/?ref_=otl_qw
www.imdb.com/list/ls083027225/?ref_=otl_2
www.imdb.com/list/ls083027225/?mode=desktop&ref_=m_ft_dsk
www.imdb.com/list/ls083027225/?qsaug=qw
www.imdb.com/list/ls083027225/?mode=desktop

3.4 如何獲取幀的時間戳資訊

每一個幀都可能攜帶有 2 個時間戳資訊，一個是解碼時間戳 dts，一個是顯示時間戳 pts，解碼時間戳告訴我們什麼時候需要解碼，顯示時間戳告訴我們什麼時候需要顯示，只有在碼流中存在 B 幀的情況下，這兩個時間戳才會不一致。

這些時間戳資訊不一定存在於碼流中（取決於生產端），如果不存在，則其值為：AV_NOPTS_VALUE

一定要選擇正確地方式列印時間戳，時間戳是使用 long long 來表示的，即 int64_t，因此列印的時候，需要使用 “%lld” 來列印，例如：

while (!interrupt) {
    int ret = av_read_frame(player->ic, &avpkt);
    if (ret < 0) {
        break;
    }
    if (avpkt.stream_index == video_stream_idx) {
        LOGD("read video frame, timestamp = %lld \n”, avpkt.pts);
    } else if (avpkt.stream_index == audio_stream_idx) {
        LOGD("read audio frame, timestamp = %lld \n”, avpkt.pts);
    }
}

由此，我們就可以通過這些 log 資訊除錯一下某一段音視訊流的時間戳是否正確，比如是否出現了時間戳的回滾和錯亂，則必然會導致播放端出現音視訊不同步或者顯示異常等情況。

相關推薦

FFMPEG Tips (3) 如何讀取每一幀的資訊

1. 碼流中每一幀的哪些資訊值得關注 ？ [ ] 音訊幀還是視訊幀 [ ] 關鍵幀還是非關鍵幀

完美解決mysql in條件語句只讀取一條資訊問題的2種方案

今天同事在編寫MYSQL查詢語句時遇到一個很奇怪的問題，使用mysql多表查詢，一個表中的某個欄位作為另一表的in查詢條件，只能讀取一條資訊，而直接用數字的話可以正常讀取

ajax請求資料動態渲染資訊流（每隔兩條資料插入一個div或者一條資訊）

1var page = 0; 2var lock = true; 3$(window).scroll(function() { 4//獲取#gg這個div到頂部的距離

FFMPEG Tips (2) 如何提取碼流的基本資訊

1. 碼流中的哪些資訊值得關注 ？ [ ] 是否包含：音訊、視訊 [ ] 碼流的封裝格式

每次取一個音訊檔案讀取一幀，這樣顯然並沒有用到所有的語音資料，

pytorch對一下常用的公開資料集有很方便的API介面，但是當我們需要使用自己的資料集訓練神經網路時，就需要自定義資料集，在pytorch中，提供了一些類，方便我們定義自己的資料集合

《組合語言》-王爽 閱讀筆記 一個讓你快速瞭解每一節在講什麼的筆記（3~4章）

第三章 3.1 記憶體中字的儲存 8086CPU中用16位暫存器來儲存一個字。採用小端法，例如：

石頭掃拖機器人 T7S 系列官宣：“每一步震動全場”，3 月 29 日見

3月24日訊息今日上午，石頭科技官方宣佈，石頭掃拖機器人 T7S 系列將於 3 月 29 日正式釋出。

位元組跳動面試題，給你一個每一項都是數值混亂順序的陣列，只要裡面正確順序的值輸出。如[5,1,3,6,2,7],只要[1,2,7]

//位元組跳動面試題，給你一個每一項都是數值混亂順序的陣列，只要裡面正確順序的值輸出，如[5,1,3,6,2,7],只要[1,2,7]

每一口都要 Keep 哦：Keep 雞胸肉 3.3 元/袋（官方 9 元）

【Keep 食品旗艦店】Keep 即食雞胸肉 80g*6 袋日常售價 59.9 元，今日下單可領 40 元大額券，實付 19.9 元包郵：天貓 Keep 即食雞胸肉 6 包 80g / 包券後 19.9 元領 40 元券摺合 3.3 元 / 包，每個 ID 可領 5 張券，

詳解mysql 獲取某個時間段每一天、每一個小時的統計資料

獲取每一天的統計資料 做專案的時候需要統對專案日誌做分析，其中有一個需求是獲取某個給定的時間段內，每一天的日誌資料，比如說要獲取從2018-02-02 09:18:36到2018-03-05 23:18:36這個時間段內，統計出每一天的日誌

oracle統計時間段內每一天的資料(推薦)

下面給大家介紹oracle統計時間段內每一天的資料，具體sql語句如下所示： 1. 生成1000個隨機數

3.redis单一持久化模式之优化配置

1.RDB最佳配置 #save 900 1 #save 300 10 #save 60 10000 dbfilename dump-${port}.rdb dir /bigdiskpath stop-writes-on-bgsave-error yes

TensorFlow實現列印每一層的輸出

在test.py中可以通過如下程式碼直接生成帶weight的pb檔案，也可以通過tf官方的freeze_graph.py將ckpt轉為pb檔案。

python 使用遞迴實現列印一個數字的每一位示例

我就廢話不多說了，直接上程式碼吧！ def func(n): # 從高分為開始列印 lengh = len(str(n))# 確定數字的長度

python:刪除離群值操作(每一行為一類資料)

刪除有多行字串的json檔案中的離群值 def processHold(eachsubject,directory,newfile): filename = \'CMUDataCol/Hold/subject{0}.json\'.format(eachsubject) # 原檔案

用.NET做B/S結構的系統，您是用幾種結構來開發，每一層之間的關係以及為什麼要這樣分層？

表現層（UI）：通俗講就是展現給使用者的介面，即使用者在使用一個系統的時候他的所見所得。

3.SpringBoot學習(一)——第一個Web應用

1.簡介 1.1 概述 Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can "just run". We take an opinionated view of the Spring platform and t

輸出"魔方陣" 所謂魔方陣是指這樣的方陣，它的每一行、每一列和對角線之和均相等。例如：

輸出"魔方陣"。所謂魔方陣是指這樣的方陣，它的每一行、每一列和對角線之和均相等。例如：

給一個不多於5位的正整數,要求:①求出它是幾位數;②分別輸出每一位數字;③按逆序輸出各位數字，例如原數為321,應輸出123

給一個不多於5位的正整數,要求:①求出它是幾位數;②分別輸出每一位數字;③按逆序輸出各位數字，例如原數為321,應輸出123。

從上到下按層列印二叉樹，同一層結點從左至右輸出。每一層輸出一行

思路：遞迴，擴容 增加一個deep引數，內部list數量與deep相同，每個深度對應一個list