recorder_engine: documentation unclear, no example (AUD-4874)

[stintel]

Environment

• Audio development kit: ESP32-S3-Box-Lite
• Module or chip used: ESP32-S3-WROOM-1
• IDF version: v4.4.5
• ADF version: v2.6-4-g5c7d67ec
• Build system: idf.py
• Running log:

  
  ESP-ROM:esp32s3-20210327
  Build:Mar 27 2021
  rst:0x15 (USB_UART_CHIP_RESET),boot:0x2a (SPI_FAST_FLASH_BOOT)
  Saved PC:0x40048d00
  SPIWP:0xee
  mode:DIO, clock div:1
  load:0x3fce3808,len:0x162c
  load:0x403c9700,len:0xbcc
  load:0x403cc700,len:0x3024
  entry 0x403c9954
  I (24) boot: ESP-IDF v4.4.5 2nd stage bootloader
  I (25) boot: compile time 16:42:10
  I (25) boot: chip revision: v0.1
  I (26) boot.esp32s3: Boot SPI Speed : 80MHz
  I (31) boot.esp32s3: SPI Mode       : DIO
  I (36) boot.esp32s3: SPI Flash Size : 2MB
  I (41) boot: Enabling RNG early entropy source...
  I (46) boot: Partition Table:
  I (50) boot: ## Label            Usage          Type ST Offset   Length
  I (57) boot:  0 nvs              WiFi data        01 02 00009000 00006000
  I (64) boot:  1 phy_init         RF data          01 01 0000f000 00001000
  I (72) boot:  2 factory          factory app      00 00 00010000 00100000
  I (79) boot: End of partition table
  I (84) esp_image: segment 0: paddr=00010020 vaddr=3c060020 size=28330h (164656) map
  I (122) esp_image: segment 1: paddr=00038358 vaddr=3fc91a00 size=025c0h (  9664) load
  I (124) esp_image: segment 2: paddr=0003a920 vaddr=40374000 size=056f8h ( 22264) load
  I (132) esp_image: segment 3: paddr=00040020 vaddr=42000020 size=59aa0h (367264) map
  I (202) esp_image: segment 4: paddr=00099ac8 vaddr=403796f8 size=08300h ( 33536) load
  I (215) boot: Loaded app from partition at offset 0x10000
  I (215) boot: Disabling RNG early entropy source...
  I (226) cpu_start: Pro cpu up.
  I (226) cpu_start: Starting app cpu, entry point is 0x403752ac
  0x403752ac: call_start_cpu1 at /opt/esp/idf/components/esp_system/port/cpu_start.c:147

I (0) cpu_start: App cpu up. I (240) cpu_start: Pro cpu start user code I (241) cpu_start: cpu freq: 160000000 I (241) cpu_start: Application information: I (243) cpu_start: Project name: esp_adf_skel I (249) cpu_start: App version: b35972e I (254) cpu_start: Compile time: Sep 6 2023 16:42:05 I (260) cpu_start: ELF file SHA256: b3ae7fd0e41ec34b... I (266) cpu_start: ESP-IDF: v4.4.5 I (271) cpu_start: Min chip rev: v0.0 I (275) cpu_start: Max chip rev: v0.99 I (280) cpu_start: Chip rev: v0.1 I (285) heap_init: Initializing. RAM available for dynamic allocation: I (292) heap_init: At 3FC95C60 len 00053AB0 (334 KiB): D/IRAM I (298) heap_init: At 3FCE9710 len 00005724 (21 KiB): STACK/DIRAM I (305) heap_init: At 3FCF0000 len 00008000 (32 KiB): DRAM I (311) heap_init: At 600FE000 len 00002000 (8 KiB): RTCRAM I (318) spi_flash: detected chip: gd I (322) spi_flash: flash io: dio W (326) spi_flash: Detected size(16384k) larger than the size in the binary image header(2048k). Using the size in the binary image header. I (340) sleep: Configure to isolate all GPIO pins in sleep state I (346) sleep: Enable automatic switching of GPIO sleep configuration I (353) cpu_start: Starting scheduler on PRO CPU. I (0) cpu_start: Starting scheduler on APP CPU. I (374) ESP_ADF_SKEL: starting E (374) REC_ENG: Invalid parameters E (374) ESP_ADF_SKEL: failed to create recorder engine I (384) ESP_ADF_SKEL: running main loop

- Compiler version: xtensa-esp32-elf-gcc (crosstool-NG esp-2021r2-patch5) 8.4.0
- Operating system:     Linux
- Using an IDE?: No
- Power supply:         USB

## Problem Description

We're investigating [recorder_engine](https://espressif-docs.readthedocs-hosted.com/projects/esp-adf/en/latest/api-reference/speech-recognition/recorder_engine.html) for use in [Willow](https://github.com/toverainc/willow). It is unclear from the documentation how to properly use it, and there are no examples using it.

### Expected Behavior

Recorder engine initializes.

### Actual Behavior

Recorder engine fails to initialize. Error message is not useful:

E (373) REC_ENG: Invalid parameters

### Steps to Reproduce

See https://github.com/toverainc/esp-skel/commit/6c89e0e438133d4fdbdeea720e36cf113e88dd7e

### Code to Reproduce This Issue

See https://github.com/toverainc/esp-skel/tree/bugreport/rec_engine/adf.

## Debug Logs

NA

## Other Items If Possible

- [ ] sdkconfig file (Attach the sdkconfig file from your project folder)
- [ ] elf file in the ``build`` folder (**Note this may contain all the code details and symbols of your project.**)
- [ ] coredump (This provides stacks of tasks.)

[jason-mao]

@stintel An open source, compatible and extensible component audio_recorder is recommended instead of recorder_engine.

[stintel]

Hi @jason-mao. Thanks for getting back to me. We're currently using audio_recorder in Willow. If use of audio_recorder is recommended instead of recorder_engine, it would be a good idea to mention that in the recorder_engine docs.

[jason-mao]

@stintel Thanks for your advice, I will fixed it.