[gstreamer-bugs] [Bug 621663] x264enc: support changing bitrate property on the fly

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=621663
  GStreamer | gst-plugins-ugly | git

--- Comment #17 from Ian Mitchell <mitch_1977muk at yahoo.co.uk> 2010-11-25 08:11:04 UTC ---
Created an attachment (id=175221)
 --> (https://bugzilla.gnome.org/attachment.cgi?id=175221)
Video encoded at an average of 250k

The constant bitrate stream.
----------------------------

The arguments are:

--threads 1 --rc-lookahead 0 --no-psy --bitrate 250 --vbv-maxrate 250
--vbv-bufsize 250 --psnr --input-res 352x288 -b 0 --no-scenecut --no-progress
-i 25 -I 25 -o video1 /devel/statmux/rawvid/quadforeman_cif

The average stream.
-------------------

Once each frame is encoded(from x264_encoder_frame_end in encoder.c) this is
called:

        if( (frameCount % 50) == 0 )
        {
            int newBitrate;

            if( test_args[0].bitrate == 350)
            {
                newBitrate = 150;
            }
            else
            {
                newBitrate = 350;
            }

            for( i=0 ; i < NO_ENCODERS ; i++ )
            {
                set_bitrate( i, newBitrate );
            }
        }

The workings of the set_bitrate function are:

x264_encoder_parameters( test_args[encoderIndex].handle , &param );
    param.rc.i_bitrate = bitrate;
    param.rc.i_vbv_max_bitrate = bitrate;
    param.rc.i_vbv_buffer_size = bitrate; /* the size = bitrate x delay, say 1
second delay at the moment so bitrate = buffer size */

    if( (ret = x264_encoder_reconfig( test_args[encoderIndex].handle, &param))
!= 0 )
    {

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