Add support for RAW audio (WAV) recording

RAW audio forwarding was supported but not for recording.

Add support for recording a raw audio stream to a `.wav` file (and
`.mkv`).

app/data/bash-completion/scrcpy

@@ -125,7 +125,7 @@ _scrcpy() {
             return
             ;;
         --record-format)
-            COMPREPLY=($(compgen -W 'mp4 mkv m4a mka opus aac flac' -- "$cur"))
+            COMPREPLY=($(compgen -W 'mp4 mkv m4a mka opus aac flac wav' -- "$cur"))
             return
             ;;
         --render-driver)

app/data/zsh-completion/_scrcpy

@@ -65,7 +65,7 @@ arguments=(
     '--push-target=[Set the target directory for pushing files to the device by drag and drop]'
     {-r,--record=}'[Record screen to file]:record file:_files'
     '--raw-key-events[Inject key events for all input keys, and ignore text events]'
-    '--record-format=[Force recording format]:format:(mp4 mkv m4a mka opus aac flac)'
+    '--record-format=[Force recording format]:format:(mp4 mkv m4a mka opus aac flac wav)'
     '--render-driver=[Request SDL to use the given render driver]:driver name:(direct3d opengl opengles2 opengles metal software)'
     '--require-audio=[Make scrcpy fail if audio is enabled but does not work]'
     '--rotation=[Set the initial display rotation]:rotation values:(0 1 2 3)'

app/scrcpy.1

@@ -355,7 +355,7 @@ Inject key events for all input keys, and ignore text events.
 
 .TP
 .BI "\-\-record\-format " format
-Force recording format (mp4, mkv, m4a, mka, opus, aac or flac).
+Force recording format (mp4, mkv, m4a, mka, opus, aac, flac or wav).
 
 .TP
 .BI "\-\-render\-driver " name

app/src/cli.c

@@ -594,8 +594,8 @@ static const struct sc_option options[] = {
         .longopt_id = OPT_RECORD_FORMAT,
         .longopt = "record-format",
         .argdesc = "format",
-        .text = "Force recording format (mp4, mkv, m4a, mka, opus, aac or "
-                "flac).",
+        .text = "Force recording format (mp4, mkv, m4a, mka, opus, aac, flac "
+                "or wav).",
     },
     {
         .longopt_id = OPT_RENDER_DRIVER,
@@ -1630,6 +1630,9 @@ get_record_format(const char *name) {
     if (!strcmp(name, "flac")) {
         return SC_RECORD_FORMAT_FLAC;
     }
+    if (!strcmp(name, "wav")) {
+        return SC_RECORD_FORMAT_WAV;
+    }
     return 0;
 }
 
@@ -2373,11 +2376,6 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
             }
         }
 
-        if (opts->audio_codec == SC_CODEC_RAW) {
-            LOGE("Recording does not support RAW audio codec");
-            return false;
-        }
-
         if (opts->video
                 && sc_record_format_is_audio_only(opts->record_format)) {
             LOGE("Audio container does not support video stream");
@@ -2403,6 +2401,20 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
                  "(try with --audio-codec=flac)");
             return false;
         }
+
+        if (opts->record_format == SC_RECORD_FORMAT_WAV
+                && opts->audio_codec != SC_CODEC_RAW) {
+            LOGE("Recording to WAV file requires a RAW audio stream "
+                 "(try with --audio-codec=raw)");
+            return false;
+        }
+
+        if ((opts->record_format == SC_RECORD_FORMAT_MP4 ||
+             opts->record_format == SC_RECORD_FORMAT_M4A)
+                && opts->audio_codec == SC_CODEC_RAW) {
+            LOGE("Recording to MP4 container does not support RAW audio");
+            return false;
+        }
     }
 
     if (opts->audio_codec == SC_CODEC_FLAC && opts->audio_bit_rate) {

app/src/options.h

@@ -26,6 +26,7 @@ enum sc_record_format {
     SC_RECORD_FORMAT_OPUS,
     SC_RECORD_FORMAT_AAC,
     SC_RECORD_FORMAT_FLAC,
+    SC_RECORD_FORMAT_WAV,
 };
 
 static inline bool
@@ -34,7 +35,8 @@ sc_record_format_is_audio_only(enum sc_record_format fmt) {
         || fmt == SC_RECORD_FORMAT_MKA
         || fmt == SC_RECORD_FORMAT_OPUS
         || fmt == SC_RECORD_FORMAT_AAC
-        || fmt == SC_RECORD_FORMAT_FLAC;
+        || fmt == SC_RECORD_FORMAT_FLAC
+        || fmt == SC_RECORD_FORMAT_WAV;
 }
 
 enum sc_codec {

app/src/recorder.c

@@ -71,6 +71,8 @@ sc_recorder_get_format_name(enum sc_record_format format) {
             return "opus";
         case SC_RECORD_FORMAT_FLAC:
             return "flac";
+        case SC_RECORD_FORMAT_WAV:
+            return "wav";
         default:
             return NULL;
     }
@@ -168,13 +170,14 @@ sc_recorder_close_output_file(struct sc_recorder *recorder) {
 }
 
 static inline bool
-sc_recorder_has_empty_queues(struct sc_recorder *recorder) {
+sc_recorder_must_wait_for_config_packets(struct sc_recorder *recorder) {
     if (recorder->video && sc_vecdeque_is_empty(&recorder->video_queue)) {
         // The video queue is empty
         return true;
     }
 
-    if (recorder->audio && sc_vecdeque_is_empty(&recorder->audio_queue)) {
+    if (recorder->audio && recorder->audio_expects_config_packet
+            && sc_vecdeque_is_empty(&recorder->audio_queue)) {
         // The audio queue is empty (when audio is enabled)
         return true;
     }
@@ -190,7 +193,7 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
     while (!recorder->stopped &&
               ((recorder->video && !recorder->video_init)
             || (recorder->audio && !recorder->audio_init)
-            || sc_recorder_has_empty_queues(recorder))) {
+            || sc_recorder_must_wait_for_config_packets(recorder))) {
         sc_cond_wait(&recorder->cond, &recorder->mutex);
     }
 
@@ -209,7 +212,8 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
     }
 
     AVPacket *audio_pkt = NULL;
-    if (!sc_vecdeque_is_empty(&recorder->audio_queue)) {
+    if (recorder->audio_expects_config_packet &&
+            !sc_vecdeque_is_empty(&recorder->audio_queue)) {
         assert(recorder->audio);
         audio_pkt = sc_vecdeque_pop(&recorder->audio_queue);
     }
@@ -597,6 +601,10 @@ sc_recorder_audio_packet_sink_open(struct sc_packet_sink *sink,
 
     recorder->audio_stream.index = stream->index;
 
+    // A config packet is provided for all supported formats except raw audio
+    recorder->audio_expects_config_packet =
+        ctx->codec_id != AV_CODEC_ID_PCM_S16LE;
+
     recorder->audio_init = true;
     sc_cond_signal(&recorder->cond);
     sc_mutex_unlock(&recorder->mutex);
@@ -709,6 +717,8 @@ sc_recorder_init(struct sc_recorder *recorder, const char *filename,
     recorder->video_init = false;
     recorder->audio_init = false;
 
+    recorder->audio_expects_config_packet = false;
+
     sc_recorder_stream_init(&recorder->video_stream);
     sc_recorder_stream_init(&recorder->audio_stream);
 

app/src/recorder.h

@@ -50,6 +50,8 @@ struct sc_recorder {
     bool video_init;
     bool audio_init;
 
+    bool audio_expects_config_packet;
+
     struct sc_recorder_stream video_stream;
     struct sc_recorder_stream audio_stream;
 

doc/recording.md

@@ -19,6 +19,7 @@ To record only the audio:
 scrcpy --no-video --record=file.opus
 scrcpy --no-video --audio-codec=aac --record=file.aac
 scrcpy --no-video --audio-codec=flac --record=file.flac
+scrcpy --no-video --audio-codec=raw --record=file.wav
 # .m4a/.mp4 and .mka/.mkv are also supported for opus, aac and flac
 ```
 
@@ -37,6 +38,7 @@ client side. Several formats (containers) are supported:
  - Matroska (`.mkv`, `.mka`)
  - OPUS (`.opus`)
  - FLAC (`.flac`)
+ - WAV (`.wav`)
 
 The container is automatically selected based on the filename.