[Libav-user] Setting the number of B-frames and P-frames

[Matteo Foglio]

Hello folks,

I am streaming from an rtsp source. It looks like half of the frames
received are key frames. Is there a way to reduce this percentage and have
a higher number of P-frames and B-frames? If possible, I would like to
increase the number of P-frames (not the one of B-frames).
I am using `pyav` which is a Python wrapper for `libav` (`ffmpeg`)

Code:

*import av*
*container = av.open(*
*    url, 'r',*
*    options={*
*        'rtsp_transport': 'tcp',*
*        'stimeout': '5000000',*
*        'max_delay': '5000000',*
*    }*
*)*
*stream = container.streams.video[0]*
*codec_context = stream.codec_context*
*codec_context.export_mvs = True*
*codec_context.gop_size = 25  *

*for packet in self.container.demux(video=0):*
*    for video_frame in packet.decode():*
*        print(video_frame.is_key_frame)*

Output:

*True*
*False*
*True*
*False*
*...*

And if I print the picture type I see:

*I*
*P*
*I*
*P*
*...*

It seems that B-frames are disabled: `codec_context.has_b_frames` is `False`

Note 1: I can't edit the camera source. I don't know if that's necessary
but I wanted to mention it. I can just edit the code used to stream the
video.

Note 2: the same solution should apply to `pyav`, `libavi` and `ffmpeg`.


Thank you!

Matteo
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