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Andrew Simpson's questions

Martin Hope
Andrew Simpson
Asked: 2024-12-11 21:36:52 +0800 CST
  • 7

Meu aplicativo usa uma conexão WiFi para funcionar. Ele escaneia os APNs disponíveis e se conecta ao mais forte disponível. Testando aqui em casa, tenho um Virgin Router (usando um Deco Mesh). Eu emito este comando:

nmcli dev wifi

Recebo isso de volta:

IN-USE  BSSID              SSID           MODE   CHAN  RATE        SIGNAL  BARS  SECURITY  
*       5C:62:8B:CA:2E:9C  dev            Infra  2     270 Mbit/s  100     ▂▄▆█  WPA2      
        62:62:8B:CA:2E:9C  --             Infra  2     270 Mbit/s  100     ▂▄▆█  WPA2      
        5C:62:8B:CA:2B:DB  dev            Infra  2     270 Mbit/s  44      â–‚â–„__  WPA2      
        FC:77:7B:65:06:08  RealiseMotion  Infra  6     195 Mbit/s  42      â–‚â–„__  WPA1 WPA2 
        40:F2:01:51:AB:02  PLUSNET-6SWC   Infra  11    130 Mbit/s  42      â–‚â–„__  WPA2      
        62:62:8B:CA:2B:DB  --             Infra  2     270 Mbit/s  37      â–‚â–„__  WPA2      
        72:97:41:57:50:1A  --             Infra  11    195 Mbit/s  37      â–‚â–„__  WPA2      
        72:97:41:57:50:1F  EE WiFi        Infra  11    195 Mbit/s  34      â–‚â–„__  --        
        70:97:41:57:50:1E  BT-6RCKK9      Infra  11    195 Mbit/s  32      â–‚â–„__  WPA2

Minha conexão doméstica é 'dev' e você pode ver que ela está listada duas vezes, mas com BSSIDs diferentes. Então,

1ª pergunta: Qual devo usar para medir força e qualidade?

2ª pergunta: Quando eu emito este comando:

nmcli con up Dev

Mas qual dos canais listados acima ele usará?

wireless-networking
Martin Hope
Andrew Simpson
Asked: 2024-11-10 16:40:04 +0800 CST
  • 7

Usando Raspberry Pi Zero 2 com Debian. Estou tentando entender/decifrar a saída usando iwconfig. Aprimorando apenas os resultados do meu próprio roteador, posso ver que usar esse comando me dá meu ESSID duas vezes, mas com propriedades de Qualidade e Sinal diferentes. Por quê?

BSS 5c:62:8b:ca:2e:9c(on wlan0)
    last seen: 1537.955s [boottime]
    TSF: 0 usec (0d, 00:00:00)
    freq: 2432
    beacon interval: 100 TUs
    capability: ESS Privacy ShortPreamble ShortSlotTime RadioMeasure (0x1431)
    signal: -28.00 dBm
    last seen: 0 ms ago
    SSID: dev
    Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0 
    DS Parameter set: channel 5
    Country: DE Environment: Indoor/Outdoor
        Channels [1 - 13] @ 20 dBm
    TPC report: TX power: 18 dBm
    ERP: <no flags>
    Extended supported rates: 24.0 36.0 48.0 54.0 
    RSN:     * Version: 1
         * Group cipher: CCMP
         * Pairwise ciphers: CCMP
         * Authentication suites: PSK
         * Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
    RM enabled capabilities:
        Capabilities: 0x73 0xd0 0x00 0x00 0x0c
            Link Measurement
            Neighbor Report
            Beacon Passive Measurement
            Beacon Active Measurement
            Beacon Table Measurement
            LCI Measurement
            Transmit Stream/Category Measurement
            Triggered Transmit Stream/Category
            FTM Range Report
            Civic Location Measurement
        Nonoperating Channel Max Measurement Duration: 0
        Measurement Pilot Capability: 4
    HT capabilities:
        Capabilities: 0x19ef
            RX LDPC
            HT20/HT40
            SM Power Save disabled
            RX HT20 SGI
            RX HT40 SGI
            TX STBC
            RX STBC 1-stream
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: No restriction (0x00)
        HT TX/RX MCS rate indexes supported: 0-15
    HT operation:
         * primary channel: 5
         * secondary channel offset: above
         * STA channel width: any
         * RIFS: 0
         * HT protection: no
         * non-GF present: 0
         * OBSS non-GF present: 0
         * dual beacon: 0
         * dual CTS protection: 0
         * STBC beacon: 0
         * L-SIG TXOP Prot: 0
         * PCO active: 0
         * PCO phase: 0
    Extended capabilities:
         * Extended Channel Switching
         * TFS
         * WNM-Sleep Mode
         * TIM Broadcast
         * BSS Transition
         * SSID List
         * Operating Mode Notification
         * Max Number Of MSDUs In A-MSDU is unlimited
    VHT capabilities:
        VHT Capabilities (0x33817992):
            Max MPDU length: 11454
            Supported Channel Width: neither 160 nor 80+80
            RX LDPC
            TX STBC
            SU Beamformer
            SU Beamformee
            RX antenna pattern consistency
            TX antenna pattern consistency
        VHT RX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT RX highest supported: 0 Mbps
        VHT TX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT TX highest supported: 0 Mbps
    VHT operation:
         * channel width: 0 (20 or 40 MHz)
         * center freq segment 1: 7
         * center freq segment 2: 0
         * VHT basic MCS set: 0xfffc
    WMM:     * Parameter version 1
         * u-APSD
         * BE: CW 15-1023, AIFSN 3
         * BK: CW 15-1023, AIFSN 7
         * VI: CW 7-15, AIFSN 2, TXOP 3008 usec
         * VO: CW 3-7, AIFSN 2, TXOP 1504 usec
    WPS:     * Version: 1.0
         * Wi-Fi Protected Setup State: 2 (Configured)
         * Response Type: 3 (AP)
         * UUID: bb16fd7a-0e68-4333-b713-5c628bca2e9a
         * Manufacturer: TP-Link
         * Model: Deco XE75
         * Model Number: Deco XE75
         * Serial Number: 0
         * Primary Device Type: 6-0050f204-1
         * Device name: Whole-home Wi-Fi
         * Config methods:
         * RF Bands: 0x3
         * Version2: 2.0
BSS 5c:62:8b:ca:2e:9d(on wlan0)
    last seen: 1537.955s [boottime]
    TSF: 0 usec (0d, 00:00:00)
    freq: 5180
    beacon interval: 100 TUs
    capability: ESS Privacy SpectrumMgmt ShortSlotTime RadioMeasure (0x1511)
    signal: -37.00 dBm
    last seen: 0 ms ago
    SSID: dev
    Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0 
    DS Parameter set: channel 36
    Country: DE Environment: Indoor/Outdoor
        Channels [36 - 36] @ 23 dBm
        Channels [40 - 40] @ 23 dBm
        Channels [44 - 44] @ 23 dBm
        Channels [48 - 48] @ 23 dBm
        Channels [52 - 52] @ 23 dBm
        Channels [56 - 56] @ 23 dBm
        Channels [60 - 60] @ 23 dBm
        Channels [64 - 64] @ 23 dBm
    Power constraint: 3 dB
    TPC report: TX power: 22 dBm
    RSN:     * Version: 1
         * Group cipher: CCMP
         * Pairwise ciphers: CCMP
         * Authentication suites: PSK
         * Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
    RM enabled capabilities:
        Capabilities: 0x73 0xd0 0x00 0x00 0x0c
            Link Measurement
            Neighbor Report
            Beacon Passive Measurement
            Beacon Active Measurement
            Beacon Table Measurement
            LCI Measurement
            Transmit Stream/Category Measurement
            Triggered Transmit Stream/Category
            FTM Range Report
            Civic Location Measurement
        Nonoperating Channel Max Measurement Duration: 0
        Measurement Pilot Capability: 4
    HT capabilities:
        Capabilities: 0x9ef
            RX LDPC
            HT20/HT40
            SM Power Save disabled
            RX HT20 SGI
            RX HT40 SGI
            TX STBC
            RX STBC 1-stream
            Max AMSDU length: 7935 bytes
            No DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: No restriction (0x00)
        HT TX/RX MCS rate indexes supported: 0-15
    HT operation:
         * primary channel: 36
         * secondary channel offset: above
         * STA channel width: any
         * RIFS: 0
         * HT protection: no
         * non-GF present: 1
         * OBSS non-GF present: 0
         * dual beacon: 0
         * dual CTS protection: 0
         * STBC beacon: 0
         * L-SIG TXOP Prot: 0
         * PCO active: 0
         * PCO phase: 0
    Extended capabilities:
         * Extended Channel Switching
         * TFS
         * WNM-Sleep Mode
         * TIM Broadcast
         * BSS Transition
         * SSID List
         * Operating Mode Notification
         * Max Number Of MSDUs In A-MSDU is unlimited
    VHT capabilities:
        VHT Capabilities (0x3381f9f6):
            Max MPDU length: 11454
            Supported Channel Width: 160 MHz
            RX LDPC
            short GI (80 MHz)
            short GI (160/80+80 MHz)
            TX STBC
            SU Beamformer
            SU Beamformee
            RX antenna pattern consistency
            TX antenna pattern consistency
        VHT RX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT RX highest supported: 0 Mbps
        VHT TX MCS set:
            1 streams: MCS 0-9
            2 streams: MCS 0-9
            3 streams: not supported
            4 streams: not supported
            5 streams: not supported
            6 streams: not supported
            7 streams: not supported
            8 streams: not supported
        VHT TX highest supported: 0 Mbps
    VHT operation:
         * channel width: 1 (80 MHz)
         * center freq segment 1: 42
         * center freq segment 2: 50
         * VHT basic MCS set: 0xfffc
    Transmit Power Envelope:
         * Local Maximum Transmit Power For 20 MHz: 23 dBm
         * Local Maximum Transmit Power For 40 MHz: 23 dBm
         * Local Maximum Transmit Power For 80 MHz: 23 dBm
         * Local Maximum Transmit Power For 160/80+80 MHz: 23 dBm
    WMM:     * Parameter version 1
         * u-APSD
         * BE: CW 15-1023, AIFSN 3
         * BK: CW 15-1023, AIFSN 7
         * VI: CW 7-15, AIFSN 2, TXOP 3008 usec
         * VO: CW 3-7, AIFSN 2, TXOP 1504 usec
    WPS:     * Version: 1.0
         * Wi-Fi Protected Setup State: 2 (Configured)
         * Response Type: 3 (AP)
         * UUID: bb16fd7a-0e68-4333-b713-5c628bca2e9a
         * Manufacturer: TP-Link
         * Model: Deco XE75
         * Model Number: Deco XE75
         * Serial Number: 0
         * Primary Device Type: 6-0050f204-1
         * Device name: Whole-home Wi-Fi
         * Config methods:
         * RF Bands: 0x3
         * Version2: 2.0
wireless-networking
Martin Hope
Andrew Simpson
Asked: 2023-02-15 05:52:01 +0800 CST
  • 6

Estou combinando imagens em um único arquivo de vídeo.

ffmpeg -y -f concat  -safe 0 -i "input.txt" -pix_fmt yuv420p "output.mp4"

dentro do arquivo input.txt existem as entradas:

file 'one.jpg'
duration 0.5
file 'two.jpg'
duration 0.246
file 'three.jpg'
duration 0.233

etc etc

Eu sei que o tamanho da imagem é 1024x720

e eu quero que eles sejam redimensionados para 352x768

É possível fazer isso em um único comando? Eu vi agora fazer isso em 2 comandos, mas isso não é bom para mim.

ffmpeg