Keep track of backend audio buffer

examples/example_audio.c

@@ -129,7 +129,7 @@ int main(int argc, char *argv[]) {
         // Refresh audio
         int queued = SDL_GetQueuedAudioSize(audio_dev);
         if(queued < AUDIO_BUFFER_SIZE) {
-            ret = Kit_GetPlayerAudioData(player, (unsigned char*)audio_buf, AUDIO_BUFFER_SIZE - queued);
+            ret = Kit_GetPlayerAudioData(player, queued, (unsigned char*)audio_buf, AUDIO_BUFFER_SIZE - queued);
             if(ret > 0) {
                 SDL_QueueAudio(audio_dev, audio_buf, ret);
             }

examples/example_complex.c

@@ -337,6 +337,7 @@ int main(int argc, char *argv[]) {
             while(need > 0) {
                 ret = Kit_GetPlayerAudioData(
                         player,
+                        queued,
                         (unsigned char*)audio_buf,
                         AUDIO_BUFFER_SIZE);
                 need -= ret;

examples/example_custom.c

@@ -184,6 +184,7 @@ int main(int argc, char *argv[]) {
             while(need > 0) {
                 ret = Kit_GetPlayerAudioData(
                         player,
+                        queued,
                         (unsigned char*)audio_buf,
                         AUDIO_BUFFER_SIZE);
                 need -= ret;

examples/example_rwops.c

@@ -177,6 +177,7 @@ int main(int argc, char *argv[]) {
             while(need > 0) {
                 ret = Kit_GetPlayerAudioData(
                         player,
+                        queued,
                         (unsigned char*)audio_buf,
                         AUDIO_BUFFER_SIZE);
                 need -= ret;

examples/example_simple.c

@@ -163,6 +163,7 @@ int main(int argc, char *argv[]) {
             while(need > 0) {
                 ret = Kit_GetPlayerAudioData(
                         player,
+                        queued,
                         (unsigned char*)audio_buf,
                         AUDIO_BUFFER_SIZE);
                 need -= ret;

include/kitchensink/internal/audio/kitaudio.h

@@ -7,7 +7,7 @@
 #include "kitchensink/kitsource.h"
 
 KIT_LOCAL Kit_Decoder* Kit_CreateAudioDecoder(const Kit_Source *src, Kit_Timer *sync_timer, int stream_index);
-KIT_LOCAL int Kit_GetAudioDecoderData(Kit_Decoder *dec, unsigned char *buf, size_t len);
+KIT_LOCAL int Kit_GetAudioDecoderData(Kit_Decoder *dec, size_t backend_buffer_size, unsigned char *buf, size_t len);
 KIT_LOCAL int Kit_GetAudioDecoderOutputFormat(const Kit_Decoder *dec, Kit_AudioOutputFormat *output);
 
 #endif // KITAUDIO_H

include/kitchensink/internal/utils/kithelpers.h

@@ -8,4 +8,6 @@
 KIT_LOCAL double Kit_GetSystemTime();
 KIT_LOCAL bool Kit_StreamIsFontAttachment(const AVStream *stream);
 
+KIT_LOCAL int min2(int a, int b);
+
 #endif // KITHELPERS_H

include/kitchensink/kitplayer.h

@@ -233,11 +233,12 @@ KIT_API int Kit_GetPlayerSubtitleData(Kit_Player *player,
  * This function will do nothing if player playback has not been started.
  * 
  * @param player Player instance
+ * @param backend_buffer_size Amount of data currently queued to the driver/hw device.
  * @param buffer Buffer to read into
  * @param length Maximum length of the buffer
  * @return Amount of data that was read, <0 on error.
  */
-KIT_API int Kit_GetPlayerAudioData(Kit_Player *player, unsigned char *buffer, int length);
+KIT_API int Kit_GetPlayerAudioData(Kit_Player *player, size_t backend_buffer_size, unsigned char *buffer, size_t length);
 
 /**
  * @brief Fetches information about the currently selected streams

src/internal/audio/kitaudio.c

@@ -227,7 +227,7 @@ static double Kit_GetCurrentPTS(const Kit_Decoder *decoder) {
     return audio_decoder->current->best_effort_timestamp * av_q2d(decoder->stream->time_base);
 }
 
-int Kit_GetAudioDecoderData(Kit_Decoder *decoder, unsigned char *buf, size_t len) {
+int Kit_GetAudioDecoderData(Kit_Decoder *decoder, size_t backend_buffer_size, unsigned char *buf, size_t len) {
     assert(decoder != NULL);
 
     Kit_AudioDecoder *audio_decoder = decoder->userdata;
@@ -240,7 +240,7 @@ int Kit_GetAudioDecoderData(Kit_Decoder *decoder, unsigned char *buf, size_t len
     if(len <= 0)
         return 0;
     if(!Kit_BeginPacketBufferRead(audio_decoder->buffer, audio_decoder->current, 0))
-        return 0;
+        goto no_data;
 
     // If packet should not yet be played, stop here and wait.
     // If packet should have already been played, skip it and try to find a better packet.
@@ -253,7 +253,7 @@ int Kit_GetAudioDecoderData(Kit_Decoder *decoder, unsigned char *buf, size_t len
         av_frame_unref(audio_decoder->current);
         Kit_FinishPacketBufferRead(audio_decoder->buffer);
         if(!Kit_BeginPacketBufferRead(audio_decoder->buffer, audio_decoder->current, 0))
-            return 0;
+            goto no_data;
         decoder->clock_pos = Kit_GetCurrentPTS(decoder);
     }
 
@@ -271,7 +271,7 @@ int Kit_GetAudioDecoderData(Kit_Decoder *decoder, unsigned char *buf, size_t len
         av_frame_unref(audio_decoder->current);
         Kit_FinishPacketBufferRead(audio_decoder->buffer);
         if(!Kit_BeginPacketBufferRead(audio_decoder->buffer, audio_decoder->current, 0))
-            return 0;
+            goto no_data;
         decoder->clock_pos = Kit_GetCurrentPTS(decoder);
     }
     //LOG("[AUDIO] >>> SYNC!: pts = %lf, sync = %lf\n", decoder->clock_pos, sync_ts);
@@ -293,4 +293,18 @@ int Kit_GetAudioDecoderData(Kit_Decoder *decoder, unsigned char *buf, size_t len
         Kit_FinishPacketBufferRead(audio_decoder->buffer);
     }
     return ret;
+
+no_data:
+    if(backend_buffer_size < 8192) {
+        len = min2(floor(len / SAMPLE_BYTES(audio_decoder)), 1024);
+        av_samples_set_silence(
+            &buf,
+            0,
+            len,
+            audio_decoder->output.channels,
+            Kit_FindAVSampleFormat(audio_decoder->output.format)
+        );
+        return len * SAMPLE_BYTES(audio_decoder);
+    }
+    return 0;
 }

src/internal/kitdecoderthread.c

@@ -8,7 +8,7 @@
 
 
 static void Kit_ProcessPacket(Kit_DecoderThread *thread, bool *pts_jumped) {
-    if(!Kit_BeginPacketBufferRead(thread->input, thread->scratch_packet, 10))
+    if(!Kit_BeginPacketBufferRead(thread->input, thread->scratch_packet, 100))
         return;
 
     // If a valid packet was found, first check if it's a control packet. Value 1 means seek.
@@ -52,7 +52,10 @@ static int Kit_DecodeMain(void *ptr) {
         // since a single data packet might contain multiple frames.
         while(SDL_AtomicGet(&thread->run) && Kit_RunDecoder(thread->decoder, &pts)) {
             if(pts_jumped) {
-                Kit_AdjustTimerBase(thread->decoder->sync_timer, pts);
+                // Note that we change the sync a bit to give decoders some time to decode.
+                // The 0.1 is essentially a hack that moves the sync time forwards a bit, so that the data getter
+                // functions wait a little bit before they start feeding again.
+                Kit_AdjustTimerBase(thread->decoder->sync_timer, pts - 0.1);
                 pts_jumped = false;
             }
         }

src/internal/kitpacketbuffer.c

@@ -252,11 +252,9 @@ void Kit_FinishPacketBufferRead(Kit_PacketBuffer *buffer) {
     advance_read(buffer);
     SDL_UnlockMutex(buffer->mutex);
     SDL_CondSignal(buffer->can_write);
-    return;
 }
 
 void Kit_CancelPacketBufferRead(Kit_PacketBuffer *buffer) {
     assert(buffer);
     SDL_UnlockMutex(buffer->mutex);
-    return;
 }

src/internal/utils/kithelpers.c

@@ -34,3 +34,7 @@ bool Kit_StreamIsFontAttachment(const AVStream *stream) {
     }
     return false;
 }
+
+int min2(int a, int b) {
+    return a < b ? a : b;
+}

src/internal/video/kitvideo.c

@@ -14,7 +14,7 @@
 #include "kitchensink/internal/video/kitvideo.h"
 
 #define KIT_VIDEO_EARLY_FAIL 1.0
-#define KIT_VIDEO_EARLY_THRESHOLD 0.01
+#define KIT_VIDEO_EARLY_THRESHOLD 0.005
 #define KIT_VIDEO_LATE_THRESHOLD 0.05
 
 typedef struct Kit_VideoDecoder {

src/kitplayer.c

@@ -229,7 +229,7 @@ int Kit_GetPlayerVideoData(Kit_Player *player, SDL_Texture *texture, SDL_Rect *a
     return Kit_GetVideoDecoderData(player->decoders[KIT_VIDEO_INDEX], texture, area);
 }
 
-int Kit_GetPlayerAudioData(Kit_Player *player, unsigned char *buffer, int length) {
+int Kit_GetPlayerAudioData(Kit_Player *player, size_t backend_buffer_size, unsigned char *buffer, size_t length) {
     assert(player != NULL);
     assert(buffer != NULL);
     if(player->decoders[KIT_AUDIO_INDEX] == NULL)
@@ -238,7 +238,7 @@ int Kit_GetPlayerAudioData(Kit_Player *player, unsigned char *buffer, int length
         return 0;
     if(player->state == KIT_PAUSED || player->state == KIT_STOPPED)
         return 0;
-    return Kit_GetAudioDecoderData(player->decoders[KIT_AUDIO_INDEX], buffer, length);
+    return Kit_GetAudioDecoderData(player->decoders[KIT_AUDIO_INDEX], backend_buffer_size, buffer, length);
 }
 
 int Kit_GetPlayerSubtitleData(Kit_Player *player, SDL_Texture *texture, SDL_Rect *sources, SDL_Rect *targets, int limit) {