ff_ffplay: merge: f1a9583305d90533acb54c9cadf6afac2c4dc3fa

ffplay: add support for interactive volume control

This is a feature heavily inspired by the mpv player. At the moment, methods
for adjusting volume in ffplay are rather clumsy: either one needs to set it
system-wide, or one needs to set it via the volume filter.

This patch adds key bindings identical to the mpv defaults for muting/unmuting
and increasing/decreasing the volume interactively without any introduction of
external dependencies.

TODO: doc update, possible mouse button bindings (mpv has this).
Signed-off-by: NGanesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: NMarton Balint <cus@passwd.hu>

ijkmedia/ijkplayer/ff_ffplay.c

@@ -992,6 +992,9 @@ static void toggle_pause(FFPlayer *ffp, int pause_on)
     SDL_UnlockMutex(ffp->is->play_mutex);
 }
 
+// FFP_MERGE: toggle_mute
+// FFP_MERGE: update_volume
+
 static void step_to_next_frame_l(FFPlayer *ffp)
 {
     VideoState *is = ffp->is;
@@ -2063,7 +2066,13 @@ static void sdl_audio_callback(void *opaque, Uint8 *stream, int len)
         len1 = is->audio_buf_size - is->audio_buf_index;
         if (len1 > len)
             len1 = len;
-        memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
+        if (!is->muted && is->audio_volume == SDL_MIX_MAXVOLUME)
+            memcpy(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1);
+        else {
+            memset(stream, is->silence_buf[0], len1);
+            if (!is->muted)
+                SDL_MixAudio(stream, (uint8_t *)is->audio_buf + is->audio_buf_index, len1, is->audio_volume);
+        }
         len -= len1;
         stream += len1;
         is->audio_buf_index += len1;
@@ -2984,6 +2993,8 @@ static VideoState *stream_open(FFPlayer *ffp, const char *filename, AVInputForma
     init_clock(&is->audclk, &is->audioq.serial);
     init_clock(&is->extclk, &is->extclk.serial);
     is->audio_clock_serial = -1;
+    is->audio_volume = SDL_MIX_MAXVOLUME;
+    is->muted = 0;
     is->av_sync_type = ffp->av_sync_type;
 
     is->play_mutex = SDL_CreateMutex();

ijkmedia/ijkplayer/ff_ffplay_def.h

@@ -93,6 +93,9 @@
 /* Calculate actual buffer size keeping in mind not cause too frequent audio callbacks */
 #define SDL_AUDIO_MAX_CALLBACKS_PER_SEC 30
 
+/* Step size for volume control */
+#define SDL_VOLUME_STEP (SDL_MIX_MAXVOLUME / 50)
+
 /* no AV sync correction is done if below the minimum AV sync threshold */
 #define AV_SYNC_THRESHOLD_MIN 0.04
 /* AV sync correction is done if above the maximum AV sync threshold */
@@ -295,6 +298,8 @@ typedef struct VideoState {
     unsigned int audio_buf1_size;
     int audio_buf_index; /* in bytes */
     int audio_write_buf_size;
+    int audio_volume;
+    int muted;
     struct AudioParams audio_src;
 #if CONFIG_AVFILTER
     struct AudioParams audio_filter_src;

ijkmedia/ijksdl/ijksdl_audio.c

@@ -37,3 +37,11 @@ void SDL_CalculateAudioSpec(SDL_AudioSpec * spec)
     spec->size *= spec->channels;
     spec->size *= spec->samples;
 }
+
+void SDL_MixAudio(Uint8*       dst,
+                  const Uint8* src,
+                  Uint32       len,
+                  int          volume)
+{
+    // do nothing;
+}

ijkmedia/ijksdl/ijksdl_audio.h

@@ -71,6 +71,8 @@ typedef uint16_t SDL_AudioFormat;
 #define AUDIO_F32SYS    AUDIO_F32MSB
 #endif
 
+#define SDL_MIX_MAXVOLUME (128)
+
 typedef void (*SDL_AudioCallback) (void *userdata, Uint8 * stream,
                                    int len);
 
@@ -89,4 +91,9 @@ typedef struct SDL_AudioSpec
 
 void SDL_CalculateAudioSpec(SDL_AudioSpec * spec);
 
+void SDL_MixAudio(Uint8*       dst,
+                  const Uint8* src,
+                  Uint32       len,
+                  int          volume);
+
 #endif