A MediaLive channel ingests live content from attached inputs, transcodes it with your encoding settings, and packages the output for delivery through MediaPackage. A channel connects three components in a live streaming workflow.
-
Inputs -- Source streams entering the channel (RTMP, Secure Reliable Transport (SRT), or MediaConnect).
-
Channel processing -- Transcoding and encoding applied to the source content (video codec, resolution, bitrate, audio codec).
-
Output groups -- Destinations where the processed content is delivered (currently MediaPackage only).
Each channel supports multiple inputs and up to 20 output groups. Within each output group, you can configure an active output and an optional standby output.
Prerequisites
Make sure that you have an Alibaba Cloud account with Intelligent Media Services (IMS) activated.
We recommend that you configure a MediaPackage channel in the Live Package module before creating a MediaLive channel. The output group requires a MediaPackage destination to deliver the stream. If no inputs are available, you can create one directly from the channel creation page. For details, see Manage inputs.
Create a channel and configure inputs
-
Log on to the IMS console. In the top left corner, select a region.
-
In the left-side navigation pane, choose . Click Create Channel.
-
Enter a custom name in the Channel Name field.
-
In the Added Inputs section, click Add.
-
In the Add Input panel, search for an input by ID or name. Select the input and click OK.
NoteIf no inputs are available, click Create Input to create one directly from the panel. For details, see Manage inputs.
-
The Edit Input Settings panel displays the Input ID, Input Name, and Input Type. Optionally, configure audio selectors for this input.
NoteAudio selectors are optional. For Real-Time Messaging Protocol (RTMP) inputs, only one audio selector is allowed.
-
Click OK to add the input. To change settings later, click Modify next to the input. The basic information section displays the input status: Online means audio and video data is being received. Offline means no data input.
-
To remove an input, click the Delete icon next to it.
Audio selector parameters
Audio selector settings differ by input protocol.
For RTMP inputs:
| Parameter | Description |
|---|---|
| Audio Selector Name | System-generated name for the selector. |
| Language Name | Custom language name. Referenced in the output configuration. |
For SRT and MediaConnect inputs:
| Parameter | Description |
|---|---|
| Audio Selector Name | System-generated name for the selector. |
| Selector Settings | Determines how audio is selected from the input. Valid values: audio language selection, audio pid selection, audio track selection. |
| Language code | Required when Selector Settings is set to audio language selection. Enter an ISO 639-2 language code. |
| PID | Required when Selector Settings is set to audio pid selection. Enter a Packet Identifier (PID). |
| Track | Required when Selector Settings is set to audio track selection. Enter one or more track IDs. |
Configure output groups
All outputs in an output group share the same protocol. MediaLive currently supports only MediaPackage as the output destination. Each output group can include an active output and an optional standby output, each with independent audio and video encoding settings.
Create an output group
-
In the Added Output Groups section, click Add.
-
Configure the output group parameters described in the following table, then click OK.
-
After the output group is added, click Modify to change settings, or click the Delete icon to remove it.
Output group parameters
| Parameter | Description |
|---|---|
| Output Group Name | Custom name. Up to 64 characters. Supports digits, letters, underscores (_), and hyphens (-). |
| Output Group Type | Only MediaPackage is supported. |
| MediaPackage Destination | GroupName: The channel group name in the Live Package module. ChannelName: The channel name in the Live Package module. The stream is pushed to the specified MediaPackage channel under the same account. |
| Output Name | Custom name for the output. |
| Manifest Name Modifier | Included in child manifest file names to distinguish between outputs. |
| Manifest Audio Group ID | Custom audio group identifier for the manifest. |
| Media Type | Type of encoding for this output. Valid values: Audio and Video, Audio, Video. |
SCTE-35 ad marker processing
SCTE-35 is an industry standard for inserting cue messages into MPEG-2 transport streams to signal ad insertion points in live content.
SCTE-35 processing is only available for SRT inputs, including SRT streams from MediaConnect.
| Parameter | Description |
|---|---|
| SCTE-35 Processing | Pass-through (default): SCTE-35 messages from the input are included in the Transport Stream (TS) segments and written to the manifest file. Do Not Pass: SCTE-35 messages are removed from the output TS segments. |
| SCTE-35 PID | Available when SCTE-35 Processing is set to Pass-through. If the input contains multiple SCTE-35 PIDs, select one to pass through. By default, MediaLive selects the first PID present on the input. If the specified PID is not present, no PID is passed. |
Video encoding settings
Select a Video Transcoding Template and a Video Codec to configure video encoding for the output.
Transcoding templates:
| Template | Max resolution | Supported codecs |
|---|---|---|
| Regular transcoding | 4K (long edge ≤ 3840, short edge ≤ 2160) | H.264, H.265 |
| Narrowband HD™ transcoding | 1080P (long edge ≤ 1920, short edge ≤ 1080) | H.264, H.265 |
Narrowband HD™ is an Alibaba Cloud transcoding technology that reduces bandwidth consumption while maintaining image quality through advanced encoding and intelligent optimization.
Video codec parameters:
| Parameter | Description |
|---|---|
| Video Output Name | Custom name for the video output. |
| Resolution | Custom width and height. If both are unspecified or set to 0, the output uses the source resolution. If only one dimension is specified, the other adapts automatically to maintain the original aspect ratio. |
| Video Bitrate | Custom video bitrate. Valid values: 50 to 6,000 kbps. If unspecified, the source specification is used. |
| Bitrate Control Mode | Valid values: ABR (Average Bitrate), CBR (Constant Bitrate), VBR (Variable Bitrate). If unspecified, the source specification is used. |
| Max Bitrate | Maximum video bitrate. Valid values: 100 to 6,000 kbps. If unspecified, the source specification is used. |
| Buffer Size | Video buffer size in kbps. If unspecified, the source specification is used. |
| Frame Rate Mode | Custom or Use Source Specification. If unspecified, the source specification is used. |
| Frame Rate | Custom frame rate, specified as a numerator and denominator. Maximum supported frame rate: 60 FPS (Frames Per Second). |
| GOP Size Unit | Unit for the Group of Pictures (GOP) size. Valid values: SECONDS, FRAMES. If unspecified, the source specification is used. |
| GOP | Custom GOP value. If unspecified, the source specification is used. |
| Number of B Frames | Custom number of B-frames (bidirectional predicted frames). If unspecified, the source specification is used. |
| H.264 Profile | Valid values: BASELINE, MAIN, HIGH. If unspecified, the source specification is used. |
Audio encoding settings
Select an Audio Encoder and configure audio parameters for the output.
| Parameter | Description |
|---|---|
| Audio Output Name | Custom name for the audio output. |
| Audio Encoder | Valid values: aac, libfdk_aac. |
| Profile | Depends on the selected encoder. For aac: AAC-LOW, AAC-MAIN. For libfdk_aac: AAC-LOW, AAC-HE, AAC-HEV2. |
| Audio Bitrate | Custom audio bitrate. If unspecified, the source specification is used. |
| Sample Rate | Custom audio sample rate. If unspecified, the source specification is used. |
| Audio Selector | Select an audio selector configured in the input settings. If unspecified, the source specification is used. |
| Language Code | A 3-character ISO 639-2 language code. If unspecified, the source specification is used. |
| Language Name | Custom language name. Supports letters, digits, spaces, underscores (_), and hyphens (-). Up to 32 UTF-8 characters. Cannot start or end with a space. If unspecified, the source specification is used. |
Start or stop a channel
After you configure all inputs and output groups, manage the channel state from the Channel Status section:
-
Click Start to begin processing.
-
Click Stop to end processing.
The Basic Information section displays channel details. To rename the channel, modify the Channel Name field.
For more information about channel state management, see Control channel state.
View channels
The Channels page lists all channels in reverse chronological order, with up to 10 per page. Click the refresh button to update the list.
| Column | Description |
|---|---|
| Channel ID/Name | Unique identifier and name of the channel. |
| Status | Current state of the channel. |
| Last Started | Timestamp of the most recent start. |
| Running Time | Duration the channel has been running. |
| Inputs | Inputs attached to the channel. |
| Output Groups | Output groups configured for the channel. |
| Actions | Available operations for the channel. |
For more details, see View channels.