How do I control the MP4 quality settings when I record and incoming RTMP stream? I want to store the highest quality rendition to MP4. Does the MP4 record what is coming in via the RTMP stream or is it transcoding? If I have multiple bit rates set up in an ABR ladder does that have any effect or is it always the “source” stream that is recorded.
If you have enabled transcoding in Wowza Streaming Engine then each bitrate of the ABR will be its own stream. Depending on the configuration of your transcoding template, the name will be like your original stream name with a suffix, e.g. “mystream_360p”. Each of these streams are fully functional streams in WSE and you can record them individually; just specify the new stream name when you call the recording functions in the REST API, or look for the designated stream in the Engine Manager panel website.
However, transcoding typically converts your incoming stream to a lower bitrate and lower quality stream. You wouldn’t normally transcode to a higher bitrate or larger resolution because upscaling does rarely make sense - you can’t magically get better quality than the input. As such, your incoming stream will likely have the best quality, and is the one you should record if quality is the main criterium.
Great, thanks for the news. So. to clarify, if I send in an H264 stream over RTMP, that exact stream without additional compression is what gets recorded to my MP4 if I record the “source” stream?
Yes, that’s correct.