Add simple WAV recording driver (audio only) (#16900)

Records unprocessed sound to a RIFF/WAVE (.wav) file,
up to 4 GB, no deps, no threads.

Makefile.common

@@ -240,6 +240,7 @@ OBJ += frontend/frontend_driver.o \
        ui/ui_companion_driver.o \
        camera/camera_driver.o \
        record/record_driver.o \
+       record/drivers/record_wav.o \
        command.o \
        msg_hash.o \
        intl/msg_hash_us.o \

griffin/griffin.c

@@ -1217,6 +1217,7 @@ WIFI
 RECORDING
 ============================================================ */
 #include "../record/record_driver.c"
+#include "../record/drivers/record_wav.c"
 #ifdef HAVE_FFMPEG
 #include "../record/drivers/record_ffmpeg.c"
 #endif

record/drivers/record_ffmpeg.c

@@ -41,7 +41,7 @@
 #include <time.h>
 #endif
 
-#include "../record_driver.h"
+#include "record_ffmpeg.h"
 
 #ifdef __cplusplus
 extern "C" {

record/drivers/record_ffmpeg.h

@@ -0,0 +1,23 @@
+/*  RetroArch - A frontend for libretro.
+ *  Copyright (c) 2024 Aleksander Mazur
+ *
+ *  RetroArch is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *  PURPOSE.  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with RetroArch.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _RECORD_FFMPEG_H
+#define _RECORD_FFMPEG_H
+
+#include "../record_driver.h"
+
+extern const record_driver_t record_ffmpeg;
+
+#endif

record/drivers/record_wav.c

@@ -0,0 +1,205 @@
+/*  RetroArch - A frontend for libretro.
+ *  Copyright (c) 2024 Aleksander Mazur
+ *
+ *  RetroArch is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *  PURPOSE.  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with RetroArch.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <retro_endianness.h>
+#include "record_wav.h"
+#include "../../verbosity.h"
+
+/**************************************/
+
+/** WAV substructure. */
+typedef struct
+{
+   uint16_t tag;        /**< Format tag. */
+   uint16_t channels;   /**< Number of channels. */
+   uint32_t sps;        /**< Samples per second. */
+   uint32_t bps;        /**< Bits per sample. */
+   uint16_t block;      /**< Bits per block (one sample for all channels). */
+   uint16_t sample;     /**< Bits per sample (single channel). */
+} waveformatex_t;
+
+/** WAV header. */
+typedef struct
+{
+   char riff[4];        /**< "RIFF" header tag. */
+   uint32_t riff_size;  /**< RIFF file size.  */
+   char fourcc[4];      /**< "WAVE" tag. */
+   char fmt_tag[4];     /**< "fmt " chunk tag. */
+   uint32_t fmt_size;   /**< Size of the following "fmt " chunk. */
+   waveformatex_t fmt;  /**< Content of "fmt " chunk. */
+   char data_tag[4];    /**< "data" chunk tag. */
+   uint32_t data_size;  /**< Size of the following "data" chunk. */
+} wav_hdr_t;
+
+/** Our private context related to a single recording. */
+typedef struct
+{
+   FILE *f;
+   unsigned frame;      /**< Bytes per sample * number of channels. */
+   uint32_t length;     /**< Bytes of audio data recorded so far. */
+} record_wav_t;
+
+#define WAV_MAX_LENGTH (0xFFFFFFFF - sizeof(wav_hdr_t))
+
+/**************************************/
+
+static bool wav_write_hdr(record_wav_t *handle, unsigned channels, unsigned samplerate)
+{
+   wav_hdr_t header = { "RIFF", };
+   uint32_t length;
+
+   if (!handle || !handle->f)
+      return false;
+
+   handle->frame       = 2 * channels;
+   /* set initial size to 4 hours; to be fixed inside record_wav_finalize */
+   length              = 4 * 60 * 60 * samplerate * handle->frame;
+   header.riff_size    = swap_if_big32(sizeof(wav_hdr_t) - offsetof(wav_hdr_t, fourcc) + length),
+   memcpy(header.fourcc, "WAVE", sizeof(header.fourcc));
+   memcpy(header.fmt_tag, "fmt ", sizeof(header.fmt_tag));
+   header.fmt_size     = swap_if_big32(sizeof(header.fmt));
+   header.fmt.tag      = swap_if_big16(1);
+   header.fmt.channels = swap_if_big16(channels);
+   header.fmt.sps      = swap_if_big16(samplerate);
+   header.fmt.bps      = swap_if_big16(samplerate * handle->frame);
+   header.fmt.block    = swap_if_big16(handle->frame);
+   header.fmt.sample   = swap_if_big16(16);
+   memcpy(header.data_tag, "data", sizeof(header.data_tag));
+   header.data_size    = swap_if_big32(length);
+
+   return fwrite(&header, sizeof(header), 1, handle->f) == 1;
+}
+
+static bool write_le32_at(FILE *f, long offset, uint32_t value)
+{
+   if (fseek(f, offset, SEEK_SET))
+      return false;
+   value = swap_if_big32(value);
+   if (fwrite(&value, sizeof(value), 1, f) != 1)
+      return false;
+
+   return true;
+}
+
+static bool wav_fix_hdr_and_close(record_wav_t *handle)
+{
+   if (!handle || !handle->f)
+      return false;
+
+   if (!write_le32_at(handle->f, offsetof(wav_hdr_t, riff_size),
+         sizeof(wav_hdr_t) - offsetof(wav_hdr_t, fourcc) + handle->length))
+      return false;
+   if (!write_le32_at(handle->f, offsetof(wav_hdr_t, data_size),
+         handle->length))
+      return false;
+   fclose(handle->f);
+   handle->f = NULL;
+   return true;
+}
+
+/**************************************/
+
+static void *record_wav_new(const struct record_params *params)
+{
+   record_wav_t *handle = calloc(1, sizeof(*handle));
+   if (!handle)
+      return NULL;
+
+   do
+   {
+      handle->f = fopen(params->filename, "wb");
+      if (!handle->f)
+      {
+         RARCH_ERR("[WAV]: Cannot create %s: %s\n",
+               params->filename, strerror(errno));
+         break;
+      }
+
+      if (!wav_write_hdr(handle, params->channels, params->samplerate))
+      {
+         RARCH_ERR("[WAV]: Cannot write header to %s: %s\n",
+               params->filename, strerror(errno));
+         break;
+      }
+
+      return handle;
+   } while (0);
+
+   free(handle);
+   return NULL;
+}
+
+static bool record_wav_push_audio(void *data,
+      const struct record_audio_data *audio_data)
+{
+   record_wav_t *handle = (record_wav_t*)data;
+   size_t frames, max, bytes;
+
+   if (!handle || !audio_data || !handle->f)
+      return false;
+
+   frames = audio_data->frames;
+   max = (WAV_MAX_LENGTH - handle->length) / handle->frame;
+   if (frames > max)
+      frames = max;
+   bytes = frames * handle->frame;
+   if (fwrite(audio_data->data, bytes, 1, handle->f) != 1)
+      return false;
+   handle->length += bytes;
+   if (frames == max)
+   {
+      /* cannot append more data */
+      RARCH_LOG("[WAV]: Size limit reached\n");
+      if (!wav_fix_hdr_and_close(handle))
+         return false;
+   }
+   return true;
+}
+
+static bool record_wav_finalize(void *data)
+{
+   record_wav_t *handle = (record_wav_t*)data;
+   if (!handle)
+      return false;
+
+   return wav_fix_hdr_and_close(handle);
+}
+
+static void record_wav_free(void *data)
+{
+   record_wav_t *handle = (record_wav_t*)data;
+   if (!handle)
+      return;
+
+   if (handle->f)
+      fclose(handle->f);
+   free(handle);
+}
+
+const record_driver_t record_wav = {
+   record_wav_new,
+   record_wav_free,
+   NULL,
+   record_wav_push_audio,
+   record_wav_finalize,
+   "wav",
+};

record/drivers/record_wav.h

@@ -0,0 +1,23 @@
+/*  RetroArch - A frontend for libretro.
+ *  Copyright (c) 2024 Aleksander Mazur
+ *
+ *  RetroArch is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ *  PURPOSE.  See the GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with RetroArch.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _RECORD_WAV_H
+#define _RECORD_WAV_H
+
+#include "../record_driver.h"
+
+extern const record_driver_t record_wav;
+
+#endif

record/record_driver.c

@@ -31,6 +31,8 @@
 #include "../defaults.h"
 
 #include "record_driver.h"
+#include "drivers/record_ffmpeg.h"
+#include "drivers/record_wav.h"
 
 static recording_state_t recording_state = {0};
 
@@ -47,6 +49,7 @@ const record_driver_t *record_drivers[] = {
 #ifdef HAVE_FFMPEG
    &record_ffmpeg,
 #endif
+   &record_wav,
    &record_null,
    NULL,
 };

record/record_driver.h

@@ -133,8 +133,6 @@ struct recording
 
 typedef struct recording recording_state_t;
 
-extern const record_driver_t record_ffmpeg;
-
 /**
  * config_get_record_driver_options:
  *