[FFmpeg-devel] [PATCH] lavfi/apad: fix logic when whole_len or pad_len options are specified

[Stefano Sabatini]

---
 libavfilter/af_apad.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/libavfilter/af_apad.c b/libavfilter/af_apad.c
index 15ba8c4..c58cacf 100644
--- a/libavfilter/af_apad.c
+++ b/libavfilter/af_apad.c
@@ -39,8 +39,8 @@ typedef struct {
     int64_t next_pts;
 
     int packet_size;
-    int64_t pad_len;
-    int64_t whole_len;
+    int64_t pad_len, pad_len_left;
+    int64_t whole_len, whole_len_left;
 } APadContext;
 
 #define OFFSET(x) offsetof(APadContext, x)
@@ -48,8 +48,8 @@ typedef struct {
 
 static const AVOption apad_options[] = {
     { "packet_size", "set silence packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, { .i64 = 4096 }, 0, INT_MAX, A },
-    { "pad_len",     "number of samples of silence to add",          OFFSET(pad_len),   AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A },
-    { "whole_len",   "target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A },
+    { "pad_len",     "set number of samples of silence to add",          OFFSET(pad_len),   AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A },
+    { "whole_len",   "set target number of samples in the audio stream", OFFSET(whole_len), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, A },
     { NULL }
 };
 
@@ -64,6 +64,8 @@ static av_cold int init(AVFilterContext *ctx)
         av_log(ctx, AV_LOG_ERROR, "Both whole and pad length are set, this is not possible\n");
         return AVERROR(EINVAL);
     }
+    apad->pad_len_left   = apad->pad_len;
+    apad->whole_len_left = apad->whole_len;
 
     return 0;
 }
@@ -73,8 +75,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
     AVFilterContext *ctx = inlink->dst;
     APadContext *apad = ctx->priv;
 
-    if (apad->whole_len)
-        apad->whole_len -= frame->nb_samples;
+    if (apad->whole_len) {
+        apad->whole_len_left = FFMAX(apad->whole_len_left - frame->nb_samples, 0);
+        av_log(ctx, AV_LOG_DEBUG, "whole_len_left:%"PRId64"\n", apad->whole_len_left);
+    }
 
     apad->next_pts = frame->pts + av_rescale_q(frame->nb_samples, (AVRational){1, inlink->sample_rate}, inlink->time_base);
     return ff_filter_frame(ctx->outputs[0], frame);
@@ -92,13 +96,14 @@ static int request_frame(AVFilterLink *outlink)
         int n_out = apad->packet_size;
         AVFrame *outsamplesref;
 
-        if (apad->whole_len > 0) {
-            apad->pad_len = apad->whole_len;
-            apad->whole_len = 0;
+        if (apad->whole_len > 0 && !apad->pad_len) {
+            apad->pad_len = apad->pad_len_left = apad->whole_len_left;
         }
-        if (apad->pad_len > 0) {
-            n_out = FFMIN(n_out, apad->pad_len);
-            apad->pad_len -= n_out;
+        if (apad->pad_len > 0 || apad->whole_len > 0) {
+            n_out = FFMIN(n_out, apad->pad_len_left);
+            apad->pad_len_left -= n_out;
+            av_log(ctx, AV_LOG_DEBUG,
+                   "n_out:%d pad_len_left:%"PRId64"\n", n_out, apad->pad_len_left);
         }
 
         if(!n_out)
-- 
1.8.3.2