Transcoding
Last update：2022-01-07 13:53:32
Basic Description
After uploading a video, you can choose to transcode or not on the video according to your business needs.
If you need to transcode your videos, transcoding template is required to be setup in advance, including resolution conversion, Bitrate, transmuxing, video encryption, and watermark adding. You can also pre-configure on upload settings when you upload videos to CloudVoD, in this case video will be transcoded once uploaded.
The function of transcoding template setting is as follows:
| Highlight Feature | Description |
|---|---|
| Re-package | Support the re-packaging for source video, including mp4, flv, hls (m3u8+ts) |
| Multi-definition Transcoding | Provides rich transcoding processing functions to convert one video file into another or multiple video files (LD/SD/HD/UH) to adapt to different network bandwidths, different terminal devices and different user needs. |
| HLS Encryption | Cloud VoD supports HLS standard encryption, which can effectively prevent video leakage and stolen links |
| H265 Encoding | Supports video compression through the H265 encoding method, which can reduce the cost by 50% compared to the encoding effect of H264. |
| Create Preview Video | You can create a preview video by setting duration, and a preview video will be created when transcoding finished. |
Operation Guide
Manage Transcoding Templates
In the left-side navigation pane, click Preferences.
Choose Transcoding. Then transcoding template list page appears.
Create a New Transcoding Template
Click New Template to create a new transcoding template.
Then the new teamplate appears.
There are two parts in transcoding template, Basic and Advanced. You can achieve simple transcoding with Basic settings, if you require further settings, you need to configure parameters in Advanced settings.
Basic
The following table describes the transcoding template parameters in Basic settings.
| Parameter | Description |
|---|---|
| Definition | There are 4 definitions by default, and the names are fixed, they are LD(Low Definition), SD(Standard Definition), HD(High Definition), and UHD(Ultra High Definition) |
| Bitrate | Valid values: 10 to 50000, in Kbit/s. The bitrate is used to control the definition. We recommend that you use the recommended bitrate for each definition. |
| Resolution | Valid values of the width or height: 128 to 4096, in pixels. You only need to set one side of the width and height. The other side is automatically set based on the aspect ratio of the video mezzanine file. |
| Frame Rate | The number of frames per second. We recommend that you use the recommended frame rate for each definition. |
| Output Format | Valid values for videos: hls, mp4, F4v and flv. |
Recommended:
| Definition | Bitrate | Resolution |
|---|---|---|
| LD | 500Kbps | 640x360 |
| SD | 800Kbps | 960x540 |
| HD | 1200Kbps | 1280x720 |
| UHD | 2000Kbps | 1920x1080 |
Advanced
| Functions | Description |
|---|---|
| Encrypted transcoding | When it is “On”, AES128 will be applied to the HLS file output. This function is mainly for customers with a strong sense of copyright protection, in order to protect videos from downloading and embezzlement, CloudVoD provides video copyright DRM encryption schemes (HLS standard encryption). |
| Delete Original File | After the transcoding is successful, only the output resolution video file is retained, and the source video file is deleted. In this way, the transcoded file cannot be re-transcoded because the source video has been deleted. |
| Create Preview Video | CloudVoD supports to create a trial viewing snippet for previewing purpose, and you can customize the duration. If it is set to 30s, the video trial URL will be output 30s from the beginning to the end. |
More Settings
Click More Settings, then the advanced setting page appears, there are four parts, including Video, Audio, Subtitle and Other.
Detailed Video Settings
| Function | Description |
|---|---|
| Video Codec | H.265 cannot be used for F4V. |
| HLS Templates | Only applicable to HLS |
| TS Duration | Only applicable to HLS. |
| Profile | Only applicable to H.264 |
| Video Scaling | Set the output aspect ratio, the default is the stretch mode, which means that if the output resolution is inconsistent with the source video resolution, the output video ratio will be deformed.Therefore, you can choose to zoom and cut, and zoom and fill the black border to ensure that it is not deformed. |
| Rotate | Rotate the video. |
| GOP Size | The interval of I frame. |
| Speed | The value ranges 0.1-10. 1 represents the original speed. The lager the value is, the faster the speed is. |
| Deinterlace | Deinterlace this video. |
| H.264 Level | The value ranges 1.0-5.1. |
| CRF | Only applicable to H.264. The value ranges 0-51. The recommended value is 18-28. The larger the value, the lower the quality is. |
| Variable Bitrate | This is only applicable when CRF is ON |
Detailed Audio Settings
| Function | Description |
|---|---|
| Audio Codec | Valid values for the HLS and MP4 container formats: AAC and MP3. |
| Profile | Only applicable to libfdk_aac. |
| Sample Rate | FLV only supports 44100/22050/11025, and aac_he profile only supports 44100&22050. |
| Bitrate | Valid values: 8 to 1000, in Kbit/s. We recommend that you use the recommended value. |
| Audio Track | We recommend that you use the recommended value. |
| Extract Audio Stream | If the audio stream of a specified language can’t be recognized , the default audio stream will be extracted. |
Detailed Subtitle Settings
| Function | Description |
|---|---|
| Extract Subtitle | It is mainly applicable to the scenario that original video contains subtitle stream (e.g. MKV), while the output video is of HLS format; 2. If the original video doesn’t contain any subtitle stream or the subtitle language cannot be recognized, no subtile will be extracted. |
Other
| Function | Description |
|---|---|
| Remove Video | If you select Remove Video, the transcoded stream does not contain video information. Generally, you can select Remove Video to extract audio, for example, in the radio station scenario. |
| Remove Audio | If you select Remove Audio, the transcoded stream does not contain audio information. If you want to generate a video stream with no sound, select this check box. |
| SEI Timestamp | You can adopt the SEI timestamp of original video, in this case, the transcoded video will have the same SEI Timestamp with the original one. If you choose “Delete”, there will be no SEI Timestamp in the transcoded videos. |
| Metadata | You can adopt the Metadata of original video, in this case, the transcoded video will have the same Metadata with the original one. |
| Migrate Metainfo to Header | If you choose “On”, the Metainfo will be migrated to head. Only applicable to MP4 and F4V. |
| Mosaic | If you want to put a mosaic in a specific area on your transcoded video, turn it on and set the startpoint and mosaic size. |
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