95 lines
3.0 KiB
ReStructuredText
95 lines
3.0 KiB
ReStructuredText
FFmpeg piping
|
|
=============
|
|
|
|
We can use *FFmpeg* to redirect / pipe input not supported by *packager*
|
|
to *packager*, for example, input from webcam devices, or rtp input. The concept
|
|
depicted here can be applied to other *FFmpeg* supported device or protocols.
|
|
|
|
Piping data to packager
|
|
-----------------------
|
|
|
|
There are two options to pipe data to packager.
|
|
|
|
- UDP socket
|
|
|
|
*FFmpeg* supports writing to a UDP socket and *packager* supports reading
|
|
from UDP sockets (See :doc:`/options/udp_file_options`)::
|
|
|
|
$ packager 'input=udp://127.0.0.1:40000,...' ...
|
|
$ ffmpeg ... -f mpegts udp://127.0.0.1:40000
|
|
|
|
VP9 cannot be carried in mpegts. Another container, e.g. webm needs to be
|
|
used when outputs VP9. In this case, transcoding has to be started after
|
|
starting packager as the initialization segment is only transmitted in the
|
|
beginning of WebM output.
|
|
|
|
- pipe
|
|
|
|
Similarily, pipe is also supported in both *FFmpeg* and *packager*::
|
|
|
|
$ mkfifo pipe1
|
|
$ packager 'input=pipe1,...' ... --io_block_size 65536
|
|
$ ffmpeg ... -f mpegts pipe: > pipe1
|
|
|
|
.. note::
|
|
|
|
Option -io_block_size 65536 tells packager to use an io_block_size of 65K
|
|
for threaded io file. This is necessary when using pipe as reading from pipe
|
|
blocks until the specified number of bytes, which is specified in
|
|
io_block_size for threaded io file, thus the value of io_block_size cannot
|
|
be too large.
|
|
|
|
Encoding / capture command
|
|
--------------------------
|
|
|
|
Camera capture
|
|
^^^^^^^^^^^^^^
|
|
|
|
Refer to `FFmpeg Capture/Webcam <https://trac.ffmpeg.org/wiki/Capture/Webcam>`_
|
|
on how to use *FFmpeg* to capture webmcam inputs.
|
|
|
|
The example assumes Mac OS X 10.7 (Lion) or later. It captures from the default
|
|
audio / video devices on the machine::
|
|
|
|
$ ffmpeg -f avfoundation -i "default" -f mpegts udp://127.0.0.1:40000
|
|
|
|
The command starts only after packager starts.
|
|
|
|
.. note::
|
|
|
|
After encoding starts, monitor encoding speed carefully. It should always be
|
|
1x and above. If not, adjust the encoding parameters to recude it.
|
|
|
|
RTP input
|
|
^^^^^^^^^
|
|
|
|
Assume there is an RTP input described by `saved_sdp_file`::
|
|
|
|
$ ffmpeg -protocol_whitelist "file,rtp,udp" -i saved_sdp_file -vcodec h264 \
|
|
-tune zerolatency -f mpegts udp://127.0.0.1:40000
|
|
|
|
.. note::
|
|
|
|
For testing, you can generate an RTP input from a static media file::
|
|
|
|
$ ffmpeg -re -stream_loop 100 -i <static.mp4> -vcodec copy -acodec \
|
|
copy -f rtp rtp://239.255.0.1:1234 -sdp_file saved_sdp_file
|
|
|
|
The command starts only after packager starts.
|
|
|
|
.. note::
|
|
|
|
After encoding starts, monitor encoding speed carefully. It should always be
|
|
1x or above. If not, adjust the encoding parameters to increase it.
|
|
|
|
Example packaging command in DASH
|
|
---------------------------------
|
|
|
|
::
|
|
|
|
$ packager \
|
|
'in=udp://127.0.0.1:40000,stream=audio,init_segment=live_cam_audio.mp4,segment_template=live_cam_audio_$Number$.m4s' \
|
|
'in=udp://127.0.0.1:40000,stream=video,init_segment=live_cam_video.mp4,segment_template=live_cam_video_$Number$.m4s' \
|
|
--mpd_output live_cam.mpd
|
|
|