operate_docs

how to use r_e_c_u_r

getting started

• prepare a usb with some videos you want to sample
• connect the hdmi output or composite (via 3.5mm trrs) to the display you want to use
• power the raspberry pi. you should see red lights on the pi board, the lcd display light up and the r_e_c_u_r splash screen on your video output
• after a few moments the interface should appear on lcd screen.
• the DSPLY key can be used to cycle through display_modes

controlling the sampler

controls

the controls on r_e_c_u_r work by mapping keys to actions. this map can be fully customised by editing the respective json file.

the default layout uses a hard mapping for every key except the < - > - ■ in red. this means every other key triggers the same actions independent of the state r_e_c_u_r is in.

the control keys ,< - > - ■ use a soft mapping. the action they trigger depends on the state , displayed on screen as control_mode in red.

these let you navigate and select folders, video files and settings when in BROWSER / SETTINGS mode, and by default control video playback (seek forward and back, pause/play) of the currently playing [NOW] sample in SAMPLER mode.

the display modes SAMPLER, BROWSER and SETTINGS are cycled by using the DSPLY key.

some actions are accessible through a function layer, toggled by the FN key.

other controls include:

• → is used to switch the [NEXT] loaded sample to the [NOW] current sample
• loading the sample in slot x into [NEXT]; where x is a key from 0 to 9
• cropping the current sample to start ([) or end (]) at the current time
• cycling forward (PRV BNK) or back (NXT BNK) through the banks of sampleS , or clearing a bank (CLR BNK)
• < SPD and > SPD are used to decrease and increase the speed of the currently playing clip (note not implemented yet)

some keys are empty to leave room for future features and user experimentation. i encourage you to modify your keymap or add custom actions you would like to use.

parts of the lcd display

PLAYER display

this section displays information about what is in the video player : the position from the start and the end of currently playing video (yellow), what slot is playing [NOW] and what slot is loaded [NEXT]

SAMPLER display mode

this is the main display mode for using r_e_c_u_r. from this view you can see details of all the samples loaded into the sampler. a bank contains 10 slots labelled 0 - 9. pressing the corresponding key will load the sample in this slot to start when the current sample finishes. the slot of the currently playing sample is highlighted.

BROWSER display mode

this is where you can load samples from your usb or internal Videos folder into the SAMPLER

• in this mode , the < and > keys will move the selection up and down
• folders are displayed ending in | for closed and / for open , the depth is displayed as indentation
• pressing the ■ key while a folder is selected toggles it open/closed
• pressing the ■ key while a video is selected loads it into the next available slot (note : you can see the first slot a video is loaded into on right column)

SETTINGS display mode

this is where you can configure r_e_c_u_r's settings.

• navigate the menu with < and > keys like above
• pressing ■ on a setting will either cycle through it's options or run an action depending on its type

MESSAGE DISPLAY

the bottom line shows the control_mode by default, but is also for messages:

• shows a yellow bar when function layer is selected
• shows a blue bar for INFO messages
• shows a red bar for ERROR messages - full message and trace for these can be found in the log files

extensions

the feature set of this project has grown beyond the simple 'seamless' video player it started out as. with more options inevitability comes more complexity and confusion. feel free to try whatever extensions interest you and ignore the rest.

capture

capture

live video-input is possible for previewing and recording. this can be enabled in the SETTINGS display mode. you need to ensure the capture type is set correctly : choose from piCamera, piCaptureSd1 or usb.

• piCamera , which reads from raspberry pi's CSI is a performant, realiable and cheap (see build docs) way to get video input into recur - note: limited to camera / rescanning
• piCaptureSd1 is a more professional solution for intergrating quality, low latency composite-video input for raspi
• usb ; with this setting the recur attempts to read video from an attached usb source. intergration, quality and performance is less predictable but i have tried it using cheap capture cards and old web cams.

with capture enabled in the settings you can toggle preview by pressing the ⦿ key. the capture input will take prioty over any video-samples playing. pressing FN + ⦿ will toggle sample recording. this can be enabled with or without preview on. the state of capture is displayed on the PLAYER display between the NOW and NEXT player infomation. after a recording is stopped the displayed state will be saving.. while the raw video-footage is converted. after this the sample can be loaded from video/internal_recordings/<date>-<count>.mp4 in browser. recur will automatically map new recordings to your current bank if there is space

NOTE: for users of piCaptureSd1: please ensure you have the composite video source active and plugged in to the HAT before powering on recur. there seems to occationally be issues with recongising the hardware otherwise and a reboot is required.

user-inputs

user-inputs

the usb-numpad is a convenient way to manually trigger discrete actions within recur (any usb-keyboards can also be used). this is fine for basic sample loading and switching however more advance features benifit from continuous control of parameters. this is where alternative user-input options are useful. (another use is to sequence recur using external gear)

usb-midi

this is by far the easiest way to control recur externally / with continuous control. plug a controller into one of recurs existing usb-sockets and set midi to usb in the SETTINGS display mode. you should see a message with the name of your device pop up. the midi-map can be configured in the same way as key-mappings.

i_n_c_u_r pcb

for anyone interested in a diy 'standalone' solution i designed a pcb that allows continous control via analog input (four knobs and four 0-5v cv inputs) + serial-midi. the build guide for this can be found here. they can also be enabled in the SETTINGS

shaders

shaders

(fragment) shaders are small text-files of glsl-code that tell your graphics card what to draw. these can be used to create your own colours, shapes and patterns on the screen. this is a good resource for getting started writing shaders. recur can load a shader in a similar way to loading a sample, and allows you to update its parameters in real time.

ensure that shaders is enabled in the settings and then use DSPLY to cycle to the SHADER display mode. here you can navigate folders and files using < > and ■ same as BROWSER/SETTINGS. selecting a shader (■) will load it, and pressing FN + 6 will toggle it on and off.

• 0-input: these shaders use no input, everything you see is generated by the code and graphics card
• 1-input: shaders can also process video. when active your current output will be passed through this shader (either from a video sample or capture preview) this is similar to the effects section on a v4 mixer except now you can create, customize and share them too !
• 2-input: allows you to perform fades, wipes and keys between two video-input sources - eg between capture preview and a video sample or two video samples (see notes below on how to set this up)

the shader parameters are best controlled by continuous inputs ( see user-inputs above) however can also be set by the numpad (somewhat clumsily):

• pressing ■ on a shader will load it; pressing ■ on the loaded shader enters SHADER_PARAM control mode (written in red at bottom)
• from here you can cycle through the params [ and ], and change the current amount with <, >. (FN + < and FN + > change the delta)
• pressing ■ will exit SHADER_PARAM control mode back to NAV_SHADER

loop vs parallel playing mode

loop vs parallel playing mode

recur was created to try loop videos seamlessly. it does this by using two video-players and preloading the NEXT player while the NOW is playing. this is most useful for short samples where a few frames every loop is very noticable. however there are some situations where this is not so important: for example when working with long samples, or when a 1080p video loaded twice maxes out the pi's memory. if you do not require the seamless switch there is now an option LOOP_TYPE to choose between loop and parallel .

• loop is the default behaviour described above
• parallel : in this mode when the current player finishes it takes a moment to load the next sample itself. there is no SWITCH action and pressing a SLOT key will start loading the corrosponding sample into this player.

introducing parallel mode also allows the possiblity of having two differnet samples playing at the same time (using roughly the same amount of memory as one in loop mode). to access the second (NEXT) player press FN + -> (player switch). you can tell which player is selected by the colour of the player bar - yellow for now, cyan for next. with next player selected you can load, seek, toggle_pause the same as normal. pressing the -> key now will 'switch' which player is displaying. (FN + ■ can manually toggle_show for the current player)

other forms of mixing between the two players can be done using the 2-input shaders mentioned above.

detour demo (frame-sampling)

detour demo

d_e_t_o_u_r is a frame-sampler created to address some limitations of sampling with video-files (eg very short loops, instant switching, varying speed and direction). although conceived as a standalone instrument i also wanted (brave) recur users to be able to test it. this is a rough integration with basic (and confusing) ui and crashes (a RESET_OPENFRAMEWORKS should recover these) use at your own risk !

to use detour_demo you must have continuous controls (either midi or i_n_c_u_r pcb). after enabling it in the settings you can cycle to FRAME_SAMPLER with DSPLY key. information about the state of the program is displayed here.

a detour is an array of frames (imagine pictures in a flip-book). the mix-shader combines sampler-input (output from recur : can be a video sample playing or capture preview) with the current frame from detour.

from the FRAME_SAMPLER display:

• pressing FN + 7 will toggle FRAME_SAMPLER mode on and off
• pressing ■ will toggle_play on the current_detour
• pressing -> will toggle_record ; this adds the output of mix-shader into the current_detour
• pressing FN + -> will toggle_record_loop ; this switches from adding by increasing the size of current_detour or overwriting an existing frame in it
• pressing 0, 1, 2, 3 will switch between different detours. for this demo the total number of frames can not exceed 500
• you can select the mix-shader type with [ and ] (it reads from your 2-input folder)
• a1 (analog input 1) will mix between the sampler-input and the current_detour (FN + [ and FN + ] are shortcuts for mix=0 and mix=1)
• a2 will set the velocity of the detour if playing or position if paused
• a3 will set the start frame of current detour
• a4 will set the end frame of current detour

this program uses the mix_shader to select the input. there is also the option to use a 1-input shader in this chain - either before the mix (only on sampler-input) or after (nice for feedbacky effects). this shader can be selected and toggled in the usual SHADER display.