Record Audio Only

[EdwardATeller]

I'd like to build an AM radio DVR. Thought I'd try to use STV as the recording engine. Is there a way to only record audio only into relatively small files?

[will]

Originally Posted by EdwardATeller

I'd like to build an AM radio DVR. Thought I'd try to use STV as the recording engine. Is there a way to only record audio only into relatively small files?

Are you going to be "watching" the radio live or will you listen to it after it records?

If it won't be a live listening then you could write a script to transcode the video recording to an audio only stream and then delete the video file. However, I've never seen STV record a file when there was a black screen so I would first see even if STV would record what you want.

[EdwardATeller]

Good idea! But I'll have to do the test you suggest first. Thank you.

[wayner]

I have had recordings of almost black screens saying something like "You are not authorized to view this channel" Or "Press Any Key to watch".

[will]

Originally Posted by wayner

I have had recordings of almost black screens saying something like "You are not authorized to view this channel" Or "Press Any Key to watch".

But that isn't a black screen, the cable box is sending out an image. I'm referencing my HVR-2250 that records ClearQAM - if the channel doesn't produce an image STV won't record anything and just throws an error.

When I tune into a cable channel I don't have access to STV doesn't throw an error, I just get the you are not authorized screen and the entire recording.

[egeller]

Ahh, Now it's coming back to me, if I understand the issue correctly.

I think it may not be possible, unless there's a parameter I do not know about. To record audio only, I think you will get a multitude of errors and no recording.

Early on there was an issue with digital stream capture. Sometimes SageDCT and OpenDCT would grab the audio but not the video. For me it was a big PIA and I wrote a Python program to check streams, while they were recording, to ensure that they had video.

I believe if you check the closed issue list you will find a bug-fix, for V9, installed in 2016 or early 2017. Sage now verifies that there is video in the stream and restarts the recording if it finds no video. If I knew how to search GitHub and closed issues, I would have looked it up.

Long story, short, I retired my Python program and have not looked back.

Erv

[Tiki]

You might be able to do something if you use OpenDCT as your tuner with ffmpeg. I think you would be able to inject a static image that would be treated as the video stream.

I believe the author of OpenDCT used this trick to display a warning message if you try to record a channel with DRM (so instead of getting a blank or unplayable recording you get a recording of an error message explaining what went wrong).

This would produce a video file that contains your audio with a static image. If you wanted an audio-only file in an audio format like mp3, you would have to go back and extract the audio track and transcode it somehow.