FAQ about live-to-VOD
Common issues and troubleshooting suggestions for the live-to-VOD process.
How many on-demand videos are generated during recording?
The number of videos generated depends on the recording period and stream interruptions. During a live stream, an on-demand video is generated each time the recording period is reached. By default, the system considers a live stream to end after a three-minute interruption, and generates an on-demand video from the content recorded until that point.
For example, the recording period is set to 30 minutes and the live stream is interrupted 38 minutes after it starts. In this case, ApsaraVideo VOD generates a 30-minute video and an 8-minute video.
What do VOD transcoding templates do?
A video-on-demand (VOD) transcoding template defines a transcoding configuration that the VOD service applies automatically to recorded videos.
If the template specifies a standard and a high definition stream, two streams are generated after transcoding.
You must create the transcoding template in the ApsaraVideo VOD console before the live stream starts.
Can I disable transcoding?
Yes. To disable transcoding, you can use the VOD service's No Transcoding template. This template uses the original video for playback. However, only the MP4, FLV, M3U8, MP3, and WEBM formats support direct playback without transcoding.
Disabling transcoding is not recommended because high-bitrate live streams may stutter during playback. If you disable transcoding, you can manually submit a transcoding job to ApsaraVideo Media Processing later. For more information, see Audio and video transcoding.
What is automatic synthesis?
ApsaraVideo VOD automatically generates one video file per recording period.
For example, if the recording period is set to 30 minutes, two on-demand videos are generated for a one-hour live stream. With automatic production enabled, ApsaraVideo VOD merges the two on-demand videos into a single video when the live stream ends and returns the produced video ID through a callback. You then have three videos in total: two on-demand videos and one merged video.
What can you do with automatic synthesis?
Typically, a short recording period is set for faster playback.
For example, an on-demand video is generated every 10 minutes after the live stream starts. With automatic production enabled, ApsaraVideo VOD merges all 10-minute on-demand videos into a single video. You can also manually call an online editing operation to produce the video.
Will a video be generated if only one video is provided?
Yes. With automatic production enabled, ApsaraVideo VOD produces a video regardless of how many source videos are generated.
For example, if the recording period is 30 minutes but the live stream lasts only 20 minutes, a 20-minute on-demand video is recorded. ApsaraVideo VOD also produces a 20-minute video from that single mezzanine file.
Is synthesis asynchronous?
Yes. Synthesis is asynchronous. You can check its status through the callback. For more information, see How to configure live-to-VOD.
What is a production and transcoding template ID?
A production and transcoding template ID specifies which transcoding template to apply to automatically produced videos. This works the same way as transcoding for regular on-demand videos.
The production and transcoding template ID does not need to match the recording template ID.
For example, you can use a recording and transcoding template that generates only a standard definition stream for quick playback. For the produced video, you can use a production and transcoding template that generates multiple streams, such as high definition, ultra high definition, and 2K. This way, intermediate on-demand videos are transcoded at a low bitrate for quick playback, while the full live stream video is transcoded at multiple bitrates after the stream ends.
Can I perform composition without transcoding?
Yes. You can use the VOD service's No Transcoding template as the production and transcoding template.
What is the maximum number of videos that can be merged in automatic video production?
Up to 40 videos can be merged in automatic video production. For example, if the recording period is set to one hour, only the videos recorded within the first 40 hours are merged. Set an appropriate recording period to stay within this limit.
What is an appropriate recording period?
One video is generated per recording period. For example, with a 30-minute recording period, a 20-minute live stream generates one video and a 70-minute live stream generates three videos.
If you do not need on-demand videos for quick playback, use the default recording period of one hour. Otherwise, set the period based on your business needs, but we recommend at least 20 minutes.