resample: implement flushing

libavresample/resample.c

@@ -52,6 +52,8 @@ struct ResampleContext {
     int padding_size;
     int initial_padding_filled;
     int initial_padding_samples;
+    int final_padding_filled;
+    int final_padding_samples;
 };
 
 
@@ -433,27 +435,57 @@ int ff_audio_resample(ResampleContext *c, AudioData *dst, AudioData *src)
         ret = ff_audio_data_combine(c->buffer, in_leftover, src, 0, in_samples);
         if (ret < 0)
             return ret;
-    } else if (!in_leftover) {
+    } else if (in_leftover <= c->final_padding_samples) {
         /* no remaining samples to flush */
         return 0;
-    } else {
-        /* TODO: pad buffer to flush completely */
     }
 
     if (!c->initial_padding_filled) {
         int bps = av_get_bytes_per_sample(c->avr->internal_sample_fmt);
         int i;
 
-        if (c->buffer->nb_samples < 2 * c->padding_size)
+        if (src && c->buffer->nb_samples < 2 * c->padding_size)
             return 0;
 
         for (i = 0; i < c->padding_size; i++)
-            for (ch = 0; ch < c->buffer->channels; ch++)
-                memcpy(c->buffer->data[ch] + bps * i,
-                       c->buffer->data[ch] + bps * (2 * c->padding_size - i), bps);
+            for (ch = 0; ch < c->buffer->channels; ch++) {
+                if (c->buffer->nb_samples > 2 * c->padding_size - i) {
+                    memcpy(c->buffer->data[ch] + bps * i,
+                           c->buffer->data[ch] + bps * (2 * c->padding_size - i), bps);
+                } else {
+                    memset(c->buffer->data[ch] + bps * i, 0, bps);
+                }
+            }
         c->initial_padding_filled = 1;
     }
 
+    if (!src && !c->final_padding_filled) {
+        int bps = av_get_bytes_per_sample(c->avr->internal_sample_fmt);
+        int i;
+
+        ret = ff_audio_data_realloc(c->buffer, in_samples + c->padding_size);
+        if (ret < 0) {
+            av_log(c->avr, AV_LOG_ERROR, "Error reallocating resampling buffer\n");
+            return AVERROR(ENOMEM);
+        }
+
+        for (i = 0; i < c->padding_size; i++)
+            for (ch = 0; ch < c->buffer->channels; ch++) {
+                if (in_leftover > i) {
+                    memcpy(c->buffer->data[ch] + bps * (in_leftover + i),
+                           c->buffer->data[ch] + bps * (in_leftover - i - 1),
+                           bps);
+                } else {
+                    memset(c->buffer->data[ch] + bps * (in_leftover + i),
+                           0, bps);
+                }
+            }
+        c->buffer->nb_samples   += c->padding_size;
+        c->final_padding_samples = c->padding_size;
+        c->final_padding_filled  = 1;
+    }
+
+
     /* calculate output size and reallocate output buffer if needed */
     /* TODO: try to calculate this without the dummy resample() run */
     if (!dst->read_only && dst->allow_realloc) {

tests/fate/libavresample.mak

@@ -38,7 +38,7 @@ fate-lavr-resample-$(3)-$(1)-$(2): CMD = avconv -i $(TARGET_PATH)/tests/data/asy
 fate-lavr-resample-$(3)-$(1)-$(2): CMP = oneoff
 fate-lavr-resample-$(3)-$(1)-$(2): CMP_UNIT = $(5)
 fate-lavr-resample-$(3)-$(1)-$(2): FUZZ = 6
-fate-lavr-resample-$(3)-$(1)-$(2): REF = $(SAMPLES)/lavr/lavr-resample-$(3)-$(1)-$(2)
+fate-lavr-resample-$(3)-$(1)-$(2): REF = $(SAMPLES)/lavr/lavr-resample-$(3)-$(1)-$(2)-v2
 endef
 
 $(call CROSS_TEST,$(SAMPLERATES),RESAMPLE,s16p,s16le,s16)