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68 lines
1.9 KiB
Plaintext
68 lines
1.9 KiB
Plaintext
AUDIO support
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-------------
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Veejay has limited audio support.
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PREPARE
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You need an AVI file with an audio track encoded in signed PCM WAVE, 44-48Khz, 2 channels (stereo) (16 bit)
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For example with ffmpeg/avconv you can use the "PCM signed 16-bit little-endian" codec named "pcm_s16le"
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# avconv myvideo.mp4 -q:v 1 -vcodec mjpeg -acodec pcm_s16le -s 1024x576 myvideo.avi
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RUN
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---
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Veejay only has support for jackd1 (the old jack)
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Start jackd prior to starting veejay :
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# jackd -d alsa -P
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Note : jack audio server must be configured with the same sampling rate as the loaded video file.
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Now, start veejay:
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# veejay -m80 /path/to/mjpeg.avi
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Use the -m commandline option to allow veejay to cache video frames when sampling. This will reduce disk latency,
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allowing for smoother audio playback (especially when used in combination of speed/pitch changes)
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The -m commandline option is further explained in docs/HowtoCache.txt
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Nota : The video you start veejay with must contains a sound stream, else the jack transport is not started ... even if -a option
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AUDIO PLAYBACK PROBLEMS
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-----------------------
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Q: What can I do about the warning "Rendering audio/video frame takes too long (measured 44 ms). Can't keep pace with audio!"
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A(1): You can start veejay with the -m commandline option. The warnings are less frequent or dissapear when the whole sample is cached in memory.
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A(2): You can disable veejay's multithreaded pixel operations:
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# export VEEJAY_MULTITHREAD_TASKS=0
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# veejay -m80 /path/to/mjpeg.avi
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A(3): Have a dedicated veejay-server machine and connect with reloaded through the network
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A(4): Run with a different video codec or lower the video resolution
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KEYS
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----
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[ a,s,d,f,g,h,j,k,l ] : Increase speed 1x,2x,3x,...
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ALT + [ a,s,d,f,g,h,j,k,l ] : Decrease speed (1/2,1/4, ...)
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KP 6 / -> : Play forward
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KP 4 / <- : Play backward
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