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Displays an RTP/JPEG stream on aSmalltv-pro (240x240 px LCD).

The roll-your-own minimalRTP/JPEG stack also works on Linux and is fully tested and fuzzed.

This is anESP-IDF 5 project.

source$IDF_PATH/export.shexport ESPPORT=/dev/ttyACM0# Configurationcp sdkconfig.defaults.ci sdkconfig.defaults# Now, change default config (e.g. WiFi credentials):idf.py menuconfigidf.py save-defconfig# Build/flash (see below for Pinout info)idf.py build flash# Lint/format./format.sh# Flash and monitoridf.py -p$ESPPORT build flash monitoridf.py -p$ESPPORT monitor# Send frames (`mtu` here means UDP payload size, not actual MTU).gst-launch-1.0 filesrc location=components/rtpjpeg/BigBuckBunny_320x180.mp4! decodebin \! videoconvert! videoscale! video/x-raw,width=240,height=240 \! jpegenc \! rtpjpegpay seqnum-offset=63000 mtu=1400 \! udpsink host=10.0.0.134 port=1234# With fps capped:gst-launch-1.0 filesrc location=components/rtpjpeg/BigBuckBunny_320x180.mp4! decodebin \! videorate!"video/x-raw,framerate=10/1"! videoconvert! videoscale! video/x-raw,width=240,height=240 \! jpegenc \! rtpjpegpay seqnum-offset=63000 mtu=1400 \! udpsink host=10.0.0.134 port=1234

• Names:buf,sz,out
• Sizes:ptrdiff_t
• Objects:typedef struct X_t {} X_t,init_X(..., X_t *out),X_do(X_t *x, ...),X_destroy(X_t *x)

• There is no WiFi provisioning - the credentials are configured via KConfig (SMALLTV_WIFI_SSID,SMALLTV_WIFI_PASSWORD) and compiled in.
• After a timeout without frames arriving (FRAME_TIMEOUT_US), a test image will be shown on the screen.
• Next to the two jitterbuffer and the JPEG data buffer to decode from, we do not have enough RAM to keep a display framebuffer.
• Thus, there is a single pixel buffer which can hold only a fraction of the screen pixels.
• Both LVGL and the JPEG decoder use this same buffer, rendering one stripe at a time, which is then sent to the display.
• When frames are arriving, LVGL is deactivated by not callinglv_timer_handler().
• We are not using the esp_jpeg component (or ROM decoder) because its API does not allow to receive decoded data block by block.

Picture:https://github.com/GeekMagicClock/smalltv-pro/blob/main/images/img-smalltv-pro.jpg

• ESP32-D0WD-V3 chip
• Xtensa® dual-core 32-bit LX6 CPU
• 448 KB of ROM
• 520 KB of SRAM
• 16 KB of RTCSRAM
• 8 MB of Flash memory (SPI)

PINs on header (verified with multimeter, WROOM module pin number in parens):

• 1 GND square
• 2 TX (35)
• 3 RX (34)
• 4 3V3
• 5 GPIO0 (25) - must be held low on reset
• 6 RST (3)

To let the programmer automatically reset the board: Connect pad 1 (GND) to pad 5 (GPIO0).