Это код мозаики GStreamer 2x2
gst-launch-1.0 -e \
videomixer name=mix \
sink_0::xpos=0 sink_0::ypos=0 sink_0::alpha=0\
sink_1::xpos=0 sink_1::ypos=0 \
sink_2::xpos=200 sink_2::ypos=0 \
sink_3::xpos=0 sink_3::ypos=100 \
sink_4::xpos=200 sink_4::ypos=100 \
rtmpsrc location='rtmp://streaming.example.com:1935/209147924'\
! decodebin name=dec1 ! videoconvert ! videoscale \
! video/x-raw,width=200,height=100 \
! mix.sink_1 \
decodebin1. ! queue ! audioconvert ! audiomixer name=amix \
rtmpsrc location='rtmp://streaming.example.com:1935/209147925'\
! decodebin name=dec2 ! videoconvert ! videoscale \
! video/x-raw,width=200,height=100 \
! mix.sink_2 \
decodebin2. ! queue ! audioconvert ! amix. \
rtmpsrc location='rtmp://streaming.example.com:1935/209147926'\
! decodebin name=dec3 ! videoconvert ! videoscale \
! video/x-raw,width=200,height=100 \
! mix.sink_3 \
decodebin3. ! queue ! audioconvert ! amix. \
rtmpsrc location='rtmp://streaming.example.com:1935/209147927'\
! decodebin name=dec4 ! videoconvert ! videoscale \
! video/x-raw,width=200,height=100 \
! mix.sink_4 \
decodebin4. ! queue ! audioconvert ! amix. \
mix. ! queue ! videoconvert ! x264enc ! flvmux name=mux streamable=true ! queue ! rtmpsink location='rtmp://streaming.example.com:1935/test'
dec1. ! queue ! audioconvert ! audiomixer name=amix \
dec2. ! queue ! audioconvert ! amix. \
dec3. ! queue ! audioconvert ! amix. \
dec4. ! queue ! audioconvert ! amix. \
amix. ! audioconvert ! audioresample ! audio/x-raw,rate=48000 ! voaacenc bitrate=96000 ! audio/mpeg ! aacparse ! audio/mpeg, mpegversion=4 ! mux.
Спасибо за прощание.Рабочий код.