From ff6342a3112e194c228660516cc19dd1ce4de6d9 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Fri, 29 Mar 2013 22:29:13 +0100
Subject: [PATCH] af_lavrresample: add no-detach suboption

Normally, af_lavrresample detaches itself immediately if the input and
output audio parameters are the same. no-detach prevents this.
---
 DOCS/man/en/af.rst             | 5 +++++
 audio/filter/af_lavrresample.c | 7 ++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/DOCS/man/en/af.rst b/DOCS/man/en/af.rst
index f3054e7255..7babf874d4 100644
--- a/DOCS/man/en/af.rst
+++ b/DOCS/man/en/af.rst
@@ -50,6 +50,11 @@ lavrresample[=option1:option2:...]
     linear
         if set then filters will be linearly interpolated between polyphase
         entries (default: no)
+    no-detach
+        don't detach if input and output audio format/rate/channels are the
+        same. You should add this option if you specify additional parameters,
+        as automatically inserted lavrresample instances will use the
+        default settings.
 
 lavcac3enc[=tospdif[:bitrate[:minchn]]]
     Encode multi-channel audio to AC-3 at runtime using libavcodec. Supports
diff --git a/audio/filter/af_lavrresample.c b/audio/filter/af_lavrresample.c
index 1d3b7639bd..2dd2c613c7 100644
--- a/audio/filter/af_lavrresample.c
+++ b/audio/filter/af_lavrresample.c
@@ -67,6 +67,7 @@ struct af_resample_opts {
 };
 
 struct af_resample {
+    int allow_detach;
     struct AVAudioResampleContext *avrctx;
     struct af_resample_opts ctx;   // opts in the context
     struct af_resample_opts opts;  // opts requested by the user
@@ -128,7 +129,8 @@ static int control(struct af_instance *af, int cmd, void *arg)
         if (((out->rate    == in->rate) || (out->rate == 0)) &&
             (out->format   == in->format) &&
             (out->bps      == in->bps) &&
-            ((out->nch     == in->nch) || out->nch == 0))
+            ((out->nch     == in->nch) || out->nch == 0) &&
+            s->allow_detach)
             return AF_DETACH;
 
         if (out->rate == 0)
@@ -224,6 +226,7 @@ static int control(struct af_instance *af, int cmd, void *arg)
             {"phase_shift",  OPT_ARG_INT,    &s->opts.phase_shift, NULL},
             {"linear",       OPT_ARG_BOOL,   &s->opts.linear, NULL},
             {"cutoff",       OPT_ARG_FLOAT,  &s->opts.cutoff, NULL},
+            {"detach",       OPT_ARG_BOOL,   &s->allow_detach, NULL},
             {0}
         };
 
@@ -307,6 +310,8 @@ static int af_open(struct af_instance *af)
         .phase_shift = 10,
     };
 
+    s->allow_detach = 1;
+
     s->avrctx = avresample_alloc_context();
     af->setup = s;