Support for 59.94 fps

[bkekelic2]

Hi,

I'm wondering if there is mechanism or possibility to set fps to 59.94 instead of 60 fps?
I see that the VideoConfig constructor accepts Int, yet not Float for fps value, so therefore I cannot put Float value there.
Maybe there is different way or idea to do so?

I'm using SingleStreamer with setVideoConfig() method.
Thanks

[ThibaultBee]

I thought the encoder only supports Integer but apparently it also supports Float: https://developer.android.com/reference/android/media/MediaFormat#KEY_FRAME_RATE

Unfortunately, from my experience the camera does not support Float range (see https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics#CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES)
There is a log when the camera starts, look for Supported FPS range list: in your logcat.

[ThibaultBee]

I made this: github.com/ThibaultBee/StreamPack/pull/new/feature/fps_as_float

The encoder should take a Float parameter for FPS, as the video source is not necessarily a camera.

Now the main question is how to handle a non integer fps for the camera. What do you think?
On the fps_as_float branch, if you try to set a non-integer fps to the camera, the camera source will throw an exception.

[ThibaultBee]

Ok.
Yes, I don't see any other solution that:

• throw an exception when the camera does support the exact bitrate
• choose the more appropriate range (in your example: [15, 60]), but the frame rate won't be stable at all

[bkekelic2]

What do you mean by "frame rate won't be stable at all"?
Now I'm experiencing interesting scenario. I set fps to 50, and when I observe stream with ffmpeg: ffplay -v verbose -vf showinfo srt://ip:port?mode=listener not all the times I've got 50 fps. Yet, almost always I can calculate ~60 fps.
I believe encoder chooses best match fps based on my "recommended" fps or?
Then, can I somehow force encoder to use exactly 50 fps?
50 is in range which you mentioned earlier [15, 60]

[ThibaultBee]

What do you mean by "frame rate won't be stable at all"?

The camera will operate between [15, 60] fps, that means it could be 15, 30, 50, 60 and there is no reason it keeps the same value over time. Have you tried to film dark scene and light scene?

Then, can I somehow force encoder to use exactly 50 fps?

The encoder is probably set with the correct value, it is your video frame provider (camera here) that provides frames between [15, 60].

On your Samsung S25, the stable framerates are 15, 24, 30 and 60.

[bkekelic2]

Thank you for valuable information and sharing general knowledge.
I did some tests and yes, I got fps range from 15 to 60 depending on the dynamics of captured image. Makes totally sense.

If, by some miracle my device would have also fps range [50, 50] how could i force it to use that correct range instead of variable range [15, 60] ? If I could...

[ThibaultBee]

If you find a way, I glad to hear it 👍