Concepts

Last updated: 2021-09-14 12:03:55

    Push

    This refers to the process in which the host pushes local video and audio sources to Tencent Video Cloud servers. It is also known as "RTMP push" in some cases.

    Playback

    It refers to live playback where the source video and audio are pulled from the Tencent Video Cloud servers and played back at the specified address after live push is implemented. The video source is generated in real time. It is only meaningful if someone pushes a live stream. Once the host stops streaming, the live streaming URL will become invalid, and since the live streams are played back in real time, no progress bar will be displayed on the player during the playback.

    Push domain name

    It refers to the domain name used to push live streams, which is a required setting. You must register the domain name before you can use it for live streaming. After a push domain name is configured, CSS will generate the corresponding push URL. For details, please see Splicing Live Stream URLs.

    Playback domain name

    It refers to the domain name used to play back live streams, which is a required setting. You must register the domain name before you can use it for live streaming. After a playback domain name is configured, CSS will generate the corresponding playback URL. For details, please see Splicing Live Stream URLs.

    Domain CNAME

    This is a domain name that is suffixed with .liveplay.myqcloud.com and is assigned by the system to the acceleration domain name configured in the CSS console. You need to configure a CNAME record at your domain name service provider. After the record takes effect, CSS will be responsible for the domain name resolution, and all requests made to this domain name will be forwarded to the edge servers of CSS.

    StreamName

    ID of a stream. StreamName and the domain name together are used to uniquely identify a stream.

    AppName

    Live streaming application name used to identify the storage path of a live streaming media file. The application name is live by default and customizable.

    Transcoding

    Transcoding is an offline task that converts a video bitstream into another. It changes the codec, resolution, bitrate, and other parameters of the bitstream for playback on different devices in varying network environments. This feature can achieve the following:

    • Increase compatibility: transcode a source video to formats that are compatible with multiple types of devices for smooth playback.
    • Increase bandwidth adaptability: transcode a source video to outputs in Smooth, SD, HD, and UHD. End users can select the bitrates as appropriate for their network conditions.
    • Reduce bandwidth usage: use advanced codecs for transcoding to substantially reduce the bitrate of a video with the original quality retained, thus lowering the payback bandwidth usage.

    H.264

    H.264 is a codec standard for highly-compressed digital video. It is developed by ITU-T Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG). It has the following advantages in transcoding:

    • Allow SD digital image (at a resolution below 1280 x 720) to transfer at a speed below 1 Mbps.
    • Deliver better image quality than other video codecs under the same bandwidth.

    H.265

    H.265 is optimized based on the video codec H.264 while reserving part of H.264 features. It has the following advantages in transcoding:

    • Allow general HD audio/video (720p at a resolution of 1280 x 720) to transfer at 1-2 Mbps.
    • Achieve the optimal balance between the bitstream, encoding quality, latency, and algorithm complexity.

    Event message notification

    When an event notification is triggered during a live push, Tencent Cloud sends the request to your server according to the configured message template, and your server authenticates and responds to the request. For more information on the response protocol, please see Event Message Notification Protocol. After the authentication is passed, your server will obtain a JSON packet containing the callback information to parse and record.

    Referer

    It is the txSecret field in the push and playback URLs. Referer is used to prevent attackers from forging your backend to generate push URLs and from stealing your playback URLs.

    Live recording

    During the push, video files generated by muxing original streams (without modifying information such as audio and video data and corresponding timestamps) can be stored on the VOD platform. To use this feature, you need to activate VOD first.

    Watermark

    To avoid your video copyright from being infringed during live push, you can add a configured watermark to the video stream during transcoding to output a watermarked video stream. The watermarks can be either texts or images.

    Screencapture

    This feature captures video images of pushed live streams in specified interval and then stores generated image files in COS. To enable screencapture, you must first grant CSS the permission to write to your COS bucket. For more information, please see Authorizing CSS to Store Screenshots in a COS Bucket.

    Porn detection

    Based on the screencapture feature, the system can perform content recognition on screenshots and send result callbacks according to the screencapture and porn detection template bound with the push domain name. For more information, please see Live Screencapture and Porn Detection.

    95th percentile bandwidth

    During the billing period, the peak bandwidth every 5 minutes is taken as a sample point. All sample points of the current month are sorted in descending order, and the top 5% are removed. The highest value of the remaining sample points is used as the 95th percentile of the monthly peak bandwidth.