57 lines
1.7 KiB
Plaintext
57 lines
1.7 KiB
Plaintext
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ffmpeg piping
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=============
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We can use *ffmpeg* to redirect / pipe input not supported by *packager*
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to *packager*, for example, input from webcam devices. The example below uses
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webcam input device. The concept depicted here can be applied to
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other *ffmpeg* supported capture device.
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ffmpeg camera capture
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---------------------
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Refer to `ffmpeg Capture/Webcam <https://trac.ffmpeg.org/wiki/Capture/Webcam>`_
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on how to use *ffmpeg* to capture webmcam inputs.
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The examples below assumes Mac OS X 10.7 (Lion) or later. It is similar on
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other platforms. Refer to the above link for details.
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Create pipe
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-----------
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We use pipe to connect *ffmpeg* and *packager*::
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$ mkfifo pipe1
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Encoding / capture command
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--------------------------
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The below command captures from the default audio / video devices on the
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machine::
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$ ffmpeg -f avfoundation -i "default" -f mpegts pipe: > pipe1
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The command starts only after packager starts.
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.. note::
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After encoding starts, monitor encoding speed carefully. It should always be
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1x and above. If not, adjust the encoding parameters to recude it.
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Packaging command (DASH)
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------------------------
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::
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$ packager \
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'in=pipe1,stream=audio,init_segment=live_cam_audio.mp4,segment_template=live_cam_audio_$Number$.m4s' \
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'in=pipe1,stream=video,init_segment=live_cam_video.mp4,segment_template=live_cam_video_$Number$.m4s' \
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--mpd_output live_cam.mpd \
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--io_block_size 65536
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.. note::
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Option -io_block_size 65536 tells packager to use an io_block_size of 65K
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for threaded io file. This is necessary as reading from pipe blocks until
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the specified number of bytes, which is specified in io_block_size for
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threaded io file, thus the value of io_block_size cannot be too large.
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