Cifrar una emisión en directo

En esta página se explica cómo cifrar el contenido de las emisiones en directo. La API Live Stream no crea ni gestiona claves de cifrado ni licencias directamente. En su lugar, debes usar un proveedor externo de gestión de derechos digitales (DRM) para estas funciones. Una vez que se hayan creado las claves de cifrado de tu contenido multimedia, pásalas a la API Live Stream mediante Secret Manager.

La configuración de cifrado se especifica en la Channel configuración. Una vez que se inicia la emisión, la canalización de vídeo de la API Live Stream empieza a cifrar tu contenido. El manifiesto de salida incluye la información necesaria para descifrar el contenido en el reproductor multimedia que elijas.

Configuraciones admitidas

Protocolo de streaming Container Sistema DRM Esquema de cifrado
HLS TS ClearKey aes128
HLS TS ClearKey sampleAes
HLS TS FairPlay sampleAes
HLS fMP4 FairPlay mpegCenc cbcs only
MPEG-DASH fMP4 ClearKey mpegCenc cenc o cbcs
MPEG-DASH fMP4 Widevine mpegCenc cenc o cbcs
HLS fMP4 Widevine mpegCenc cenc o cbcs
MPEG-DASH fMP4 PlayReady mpegCenc cenc o cbcs
HLS fMP4 PlayReady mpegCenc cenc o cbcs

Añadir la clave de cifrado a Secret Manager

Antes de empezar, crea tus claves de cifrado con el proveedor de DRM de terceros que elijas.

La API Live Stream requiere que tu secreto contenga la clave de cifrado en el siguiente formato JSON, junto con otra información necesaria.

Consulte la documentación del protocolo DRM para ver una descripción de cada campo. Ten en cuenta que debes convertir de snake case a camel case para el formato JSON.

Ejemplo de código JSON

{
  "encryptionKeys": [
    {
      // Key for FairPlay configuration.
      "keyId": "d569cb35bd0548c7a99d92feb381df13",
      "key": "f1967daca83e81f38d80aa741e7b32c2",
      "iv": "8d80aa741e7b32c2f1967daca83e81f3",
      "keyUri": "skd://d569cb35bd0548c7a99d92feb381df13",
      "matchers": [
        {
          "muxStreams": ["ts_fairplay"]
        }
      ]
    },
    {
      // Key for Widevine configurations.
      "keyId": "44ec248b048c43a6a6ee58a752c6f9f8",
      "key": "f1967daca83e81f38d80aa741e7b32c2",
      "keyUri": "skd://44ec248b048c43a6a6ee58a752c6f9f8",
      "matchers": [
        {
          "muxStreams": [
            "fmp4_widevine_cenc_video",
            "fmp4_widevine_cenc_audio",
            "fmp4_widevine_cbcs_video",
            "fmp4_widevine_cbcs_audio"
          ]
        }
      ]
    },
    {
      // Key for PlayReady configurations.
      "keyId": "8beed229709f480bb6004ec0f33e82d1",
      "key": "ad20cd838f354dcc8a77c443d08ff09f",
      "keyUri": "skd://8beed229709f480bb6004ec0f33e82d1",
      "matchers": [
        {
          "muxStreams": [
            "fmp4_playready_cenc_video",
            "fmp4_playready_cenc_audio",
            "fmp4_playready_cbcs_video",
            "fmp4_playready_cbcs_audio"
          ]
        }
      ]
    },
    {
      // Key for all ClearKey configurations.
      "keyId": "3d9dccb479c64adbb6e514790caa7822",
      "key": "f1967daca83e81f38d80aa741e7b32c2",
      "keyUri": "https://example.com/keys/3d9dccb479c64adbb6e514790caa7822.bin",
      "iv": "8d80aa741e7b32c2f1967daca83e81f3"
      // No `matchers` field. This is the default key to use when none of the keys above match.
    }
  ]
}

Si tu configuración de cifrado (por ejemplo, FairPlay) requiere un vector de inicialización (VI) explícito, pero no se incluye, la API usará el valor de keyId para el valor de iv.

Para añadir tu clave de cifrado, haz una de las siguientes acciones:

A continuación, haz lo siguiente para configurar tu clave de cifrado:

  1. Configura los permisos de IAM en tu secreto para que la API Live Stream pueda acceder al contenido del secreto. Para ello, concede el rol secretmanager.secretAccessor a la cuenta de servicio service-PROJECT_NUMBER@gcp-sa-livestream.iam.gserviceaccount.com (de forma similar a como la cuenta de servicio tiene acceso a tus segmentos de Cloud Storage).
  2. Busca el nombre de recurso de la versión del secreto que has creado (por ejemplo, projects/PROJECT_NUMBER/secrets/SECRET_ID/versions/VERSION_ID). Necesitas este nombre para configurar el canal.

Configurar el canal

La configuración de cifrado se especifica mediante objetos del array encryptions a nivel de Channel. Se asigna un identificador único (id) a cada configuración. Cada muxStream usa un identificador para indicar qué configuración de cifrado se debe usar o omite ese campo para que no se cifre.

Formato JSON

{
  // other channel settings …
  "encryptions": [
    {
      // Identifier for this encryption configuration, to be specified in muxStream(s).
      "id": string,
      // Configuration for secrets stored in Google Secret Manager.
      "secretManagerKeySource": {
        // The name of the Secret Version containing the encryption key.
        // `projects/{project}/secrets/{secret_id}/versions/{version_number}`
        // Using {version_number} of `latest` is not supported.
        "secretVersion": string
      },
      // DRM system(s) that will be used. At least one must be specified. If a DRM system
      // is omitted, it will be considered disabled.
      "drmSystems": {
        // Widevine configuration.
        "widevine": {},
        // FairPlay configuration.
        "fairplay": {},
        // PlayReady configuration.
        "playready": {},
        // ClearKey configuration.
        "clearkey": {}
      },
      // Union field encryption_mode can be only one of the following:
      // Configuration for HLS AES-128 encryption.
      "aes128": {},
      // Configuration for HLS SAMPLE-AES encryption.
      "sampleAes": {},
      // Configuration for MPEG-DASH Common Encryption (MPEG-CENC).
      "mpegCenc": {
        // Specify the encryption scheme. Supported schemes:
        // - `cenc` - AES-CTR subsample
        // - `cbcs`- AES-CBC subsample pattern
        "scheme": string
      }
      // End of list of possible types for union field encryption_mode.
    }
    // Any other encryption configurations.
  ],
  "muxStreams": [
    {
      // Unique identifier for the muxStream.
      "key": string,
      // Identifier of the encryption configuration for the muxStream.
      "encryptionId": string
      // … other muxStream settings.
    }
    // Other muxStreams.
  ],

  // Other channel settings.
}

Ejemplo (ClearKey)

En el siguiente ejemplo se configuran muxStreams AES-128 y SAMPLE-AES en manifiestos HLS, y muxStreams MPEG-CENC (cenc y cbcs) en manifiestos DASH:

"elementaryStreams": [
  {
    "key": "es_video",
    "videoStream": {
      "h264": {
        "profile": "main",
        "heightPixels": 600,
        "widthPixels": 800,
        "bitrateBps": 1000000,
        "frameRate": 60,
      },
    },
  },
  {
    "key": "es_audio",
    "audioStream": {
      "codec": "aac",
      "channelCount": 2,
      "bitrateBps": 160000
    }
  }
],
"encryptions": [
  {
    "id": "aes-128",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"clearkey": {}},
    "aes128": {}
  },
  {
    "id": "sample-aes",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"clearkey": {}},
    "sampleAes": {}
  },
  {
    "id": "cenc",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"clearkey": {}},
    "mpegCenc": {
      "scheme": "cenc"
    }
  },
  {
    "id": "cbcs",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"clearkey": {}},
    "mpegCenc": {
      "scheme": "cbcs"
    }
  }
],
"muxStreams": [
  {
    "key": "ts_aes128",
    "container": "ts",
    "elementaryStreams": ["es_video", "es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "aes-128"
  },
  {
    "key": "ts_sampleaes",
    "container": "ts",
    "elementaryStreams": ["es_video", "es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "sample-aes"
  },
  {
    "key": "fmp4_cenc_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "cenc"
  },
  {
    "key": "fmp4_cenc_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "cenc"
  },
  {
    "key": "fmp4_cbcs_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "cbcs"
  },
  {
    "key": "fmp4_cbcs_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "cbcs"
  }
],
"manifests": [
  {
    "key": "manifest_aes128_hls",
    "fileName": "manifest_aes128.m3u8",
    "type": "HLS",
    "muxStreams": ["ts_aes128"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_sampleaes_hls",
    "fileName": "manifest_sampleaes.m3u8",
    "type": "HLS",
    "muxStreams": ["ts_sampleaes"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_cenc_dash",
    "fileName": "manifest_cenc.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_cenc_video", "fmp4_cenc_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_cbcs_dash",
    "fileName": "manifest_cbcs.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_cbcs_video", "fmp4_cbcs_audio"],
    "maxSegmentCount": 10
  }
]

Ejemplo (FP/PR/Widevine)

En el siguiente ejemplo se configuran los muxStreams de FairPlay/SAMPLE-AES, Widevine/MPEG-CENC (cenc y cbcs) y PlayReady/MPEG-CENC (cenc y cbcs). Los muxStreams de Widevine y PlayReady se incluyen en los manifiestos HLS y DASH.

"elementaryStreams": [
  {
    "key": "es_video",
    "videoStream": {
      "h264": {
        "profile": "main",
        "heightPixels": 600,
        "widthPixels": 800,
        "bitrateBps": 1000000,
        "frameRate": 60,
      },
    },
  },
  {
    "key": "es_audio",
    "audioStream": {
      "codec": "aac",
      "channelCount": 2,
      "bitrateBps": 160000
    }
  }
],
"encryptions": [
  {
    "id": "fairplay",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"fairplay": {}},
    "sampleAes": {}
  },
  {
    "id": "widevine-cenc",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"widevine": {}},
    "mpegCenc": {
      "scheme": "cenc"
    }
  },
  {
    "id": "widevine-cbcs",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"widevine": {}},
    "mpegCenc": {
      "scheme": "cbcs"
    }
  },
  {
    "id": "playready-cenc",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"playready": {}},
    "mpegCenc": {
      "scheme": "cenc"
    }
  },
  {
    "id": "playready-cbcs",
    "secretManagerKeySource": {
      "secretVersion": "projects/12345/secrets/key-1/versions/1"
    },
    "drmSystems": {"playready": {}},
    "mpegCenc": {
      "scheme": "cbcs"
    }
  }
],
"muxStreams": [
  {
    "key": "ts_fairplay",
    "container": "ts",
    "elementaryStreams": ["es_video", "es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "fairplay"
  },
  {
    "key": "fmp4_widevine_cenc_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "widevine-cenc"
  },
  {
    "key": "fmp4_widevine_cenc_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "widevine-cenc"
  },
  {
    "key": "fmp4_widevine_cbcs_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "widevine-cbcs"
  },
  {
    "key": "fmp4_widevine_cbcs_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "widevine-cbcs"
  },
  {
    "key": "fmp4_playready_cenc_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "playready-cenc"
  },
  {
    "key": "fmp4_playready_cenc_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "playready-cenc"
  },
  {
    "key": "fmp4_playready_cbcs_video",
    "container": "fmp4",
    "elementaryStreams": ["es_video"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "playready-cbcs"
  },
  {
    "key": "fmp4_playready_cbcs_audio",
    "container": "fmp4",
    "elementaryStreams": ["es_audio"],
    "segmentSettings": {"segmentDuration": "2s"},
    "encryptionId": "playready-cbcs"
  }
],
"manifests": [
  {
    "key": "manifest_fairplay_hls",
    "fileName": "manifest_fairplay.m3u8",
    "type": "HLS",
    "muxStreams": ["ts_fairplay"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_widevine_cenc_hls",
    "fileName": "manifest_widevine_cenc.m3u8",
    "type": "HLS",
    "muxStreams": ["fmp4_widevine_cenc_video", "fmp4_widevine_cenc_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_widevine_cbcs_hls",
    "fileName": "manifest_widevine_cbcs.m3u8",
    "type": "HLS",
    "muxStreams": ["fmp4_widevine_cbcs_video", "fmp4_widevine_cbcs_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_widevine_cenc_dash",
    "fileName": "manifest_widevine_cenc.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_widevine_cenc_video", "fmp4_widevine_cenc_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_widevine_cbcs_dash",
    "fileName": "manifest_widevine_cbcs.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_widevine_cbcs_video", "fmp4_widevine_cbcs_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_playready_cenc_hls",
    "fileName": "manifest_playready_cenc.m3u8",
    "type": "HLS",
    "muxStreams": ["fmp4_playready_cenc_video", "fmp4_playready_cenc_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_playready_cbcs_hls",
    "fileName": "manifest_playready_cbcs.m3u8",
    "type": "HLS",
    "muxStreams": ["fmp4_playready_cbcs_video", "fmp4_playready_cbcs_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_playready_cenc_dash",
    "fileName": "manifest_playready_cenc.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_playready_cenc_video", "fmp4_playready_cenc_audio"],
    "maxSegmentCount": 10
  },
  {
    "key": "manifest_playready_cbcs_dash",
    "fileName": "manifest_playready_cbcs.mpd",
    "type": "DASH",
    "muxStreams": ["fmp4_playready_cbcs_video", "fmp4_playready_cbcs_audio"],
    "maxSegmentCount": 10
  }
]

Una vez que sepas la configuración JSON que quieres usar, crea un canal de la forma habitual.

Iniciar la transmisión

Una vez que se haya creado el canal, inícialo y envía la emisión de entrada.

Cuando se inicia el canal, la API Live Stream obtiene la clave de cifrado identificada por secretVersion de Secret Manager. Si la API Live Stream no puede obtener la clave o esta tiene un formato irreconocible, el estado del canal pasa a ser STREAMING_ERROR. Si la clave se obtiene correctamente, el estado del canal pasa a ser AWAITING_INPUT, como de costumbre.

Una vez que empieza la emisión, la API Live Stream empieza a cifrar el contenido de salida según la configuración proporcionada en el momento de la creación.

Monitorizar el resultado

Los flujos de salida cifrados contienen manifiestos modificados con la información necesaria para descifrar el contenido y reproducirlo.

Ejemplos de manifiestos

Los siguientes manifiestos muestran la información necesaria para descifrar el contenido asociado.

HLS AES-128/ClearKey

#EXTM3U
#EXT-X-VERSION:7
#EXT-X-TARGETDURATION:4
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-DISCONTINUITY-SEQUENCE:0
#EXT-X-KEY:METHOD=AES-128,URI="https://example.com/keys/3d9dccb479c64adbb6e514790caa7822.bin",IV=0x8d80aa741e7b32c2f1967daca83e81f3
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:22.870Z
#EXTINF:2.576778
segment-0000000000.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:25.447Z
#EXTINF:2.000000
segment-0000000001.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:27.447Z
#EXTINF:2.000000
segment-0000000002.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:29.447Z
#EXTINF:2.000000
segment-0000000003.ts

HLS SAMPLE-AES/FairPlay

#EXTM3U
#EXT-X-VERSION:7
#EXT-X-TARGETDURATION:4
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-DISCONTINUITY-SEQUENCE:0
#EXT-X-KEY:METHOD=SAMPLE-AES,URI="skd://d569cb35bd0548c7a99d92feb381df13",KEYFORMAT="com.apple.streamingkeydelivery",KEYFORMATVERSIONS="1"
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:22.870Z
#EXTINF:2.576778
segment-0000000000.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:25.447Z
#EXTINF:2.000000
segment-0000000001.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:27.447Z
#EXTINF:2.000000
segment-0000000002.ts
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:29.447Z
#EXTINF:2.000000
segment-0000000003.ts

HLS MPEG-CENC/Widevine

#EXTM3U
#EXT-X-VERSION:7
#EXT-X-TARGETDURATION:4
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-DISCONTINUITY-SEQUENCE:0
#EXT-X-KEY:METHOD=SAMPLE-AES-CTR,URI="data:text/plain;base64,AAAAOHBzc2gAAAAA7e+LqXnWSs6jyCfSEAB3Gcrj/8kFtioyiVbJMh9I49yVmwY=",KEYFORMAT="urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed",KEYFORMATVERSIONS="1"
#EXT-X-MAP:URI="segment-initialization_segment_0000000000.m4s"
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:22.870Z
#EXTINF:2.576778
segment-0000000000.m4s
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:25.447Z
#EXTINF:2.000000
segment-0000000001.m4s
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:27.447Z
#EXTINF:2.000000
segment-0000000002.m4s
#EXT-X-PROGRAM-DATE-TIME:2022-10-12T20:08:29.447Z
#EXTINF:2.000000
segment-0000000003.m4s

DASH MPEG-CENC/Widevine

<AdaptationSet segmentAlignment="true" maxWidth="800" maxHeight="600">
  <Representation mimeType="video/mp4" id="fmp4_widevine_cenc_video" codecs="avc1.4d001f">
    <ContentProtection value="cenc" schemeIdUri="urn:mpeg:dash:mp4protection:2011" cenc:default_KID="44ec248b-048c-43a6-a6ee-58a752c6f9f8"/>
    <ContentProtection schemeIdUri="urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed" value="Widevine">
      <cenc:pssh>AAAAOHBzc2gAAAAA7e+LqXnWSs6jCfc1R0h7QAAABgSEAB3Gcrj/8kFklokiVbJMh9VmwY=</cenc:pssh>
    </ContentProtection>
  </Representation>
</AdaptationSet>
<AdaptationSet segmentAlignment="true" mimeType="audio/mp4" id="1" label="fmp4_widevine_cenc_audio">
  <Representation id="fmp4_widevine_cenc_audio" codecs="mp4a.40.2">
    <ContentProtection value="cenc" schemeIdUri="urn:mpeg:dash:mp4protection:2011" cenc:default_KID="44ec248b-048c-43a6-a6ee-58a752c6f9f8"/>
    <ContentProtection schemeIdUri="urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed" value="Widevine">
      <cenc:pssh>AAAAOHBzc2gAAAAA7e+LqXnWSs6jCfc1R0h7QAAABgSEAB3Gcrj/8kFklokiVbJMh9VmwY=</cenc:pssh>
    </ContentProtection>
  </Representation>
</AdaptationSet>

Se recomienda usar reproductores basados en HLS.js para descifrar HLS/TS. Se recomienda usar reproductores basados en Shaka Player para descifrar DASH o fMP4.

El esquema "cenc" de PlayReady es compatible con máquinas físicas que ejecutan Windows 10 con el navegador Microsoft Edge, Xbox One (versión 1703 o inferior) y algunos dispositivos que no son Windows (por ejemplo, smart TVs). El esquema "cbcs" de PlayReady solo es compatible con Xbox One versión 1709 o posterior. Consulta más información sobre los modos de cifrado de contenido de PlayReady.

Actualizar la clave de cifrado

Puedes cambiar tu canal para que use nuevas claves de cifrado sin detener la emisión ni reiniciar el canal.

Para actualizar las claves, primero añade las nuevas claves a Secret Manager. Las nuevas claves pueden ser una nueva versión de tu secreto o un secreto nuevo. Si creas un secreto, asegúrate de que la API Live Stream tenga el rol secretmanager.secretAccessor para ese secreto.

Una vez que las nuevas claves estén en Secret Manager, crea un evento de actualización de cifrados. Se actualiza cualquier ajuste de cifrado especificado en el cuerpo de la solicitud. Los ajustes que no se especifiquen no se modificarán.