From 52bd9cb4d29bc086f45f239c56a6a3c63406a073 Mon Sep 17 00:00:00 2001
From: Stefano Sabatini <stefasab@gmail.com>
Date: Mon, 30 Jul 2012 19:46:36 +0200
Subject: [PATCH] lavfi/movie: force channel layout if not set by the decoder

This ensures that the output buffers will have the channel layout set,
which is required by filters.

Also consistent with ffmpeg.c behavior.
---
 libavfilter/src_movie.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/libavfilter/src_movie.c b/libavfilter/src_movie.c
index a4a12939e2..56e7083869 100644
--- a/libavfilter/src_movie.c
+++ b/libavfilter/src_movie.c
@@ -162,6 +162,29 @@ static int open_stream(void *log, MovieStream *st)
     return 0;
 }
 
+static int guess_channel_layout(MovieStream *st, int st_index, void *log_ctx)
+{
+    AVCodecContext *dec_ctx = st->st->codec;
+    char buf[256];
+    int64_t chl = av_get_default_channel_layout(dec_ctx->channels);
+
+    if (!chl) {
+        av_log(log_ctx, AV_LOG_ERROR,
+               "Channel layout is not set in stream %d, and could not "
+               "be guessed from the number of channels (%d)\n",
+               st_index, dec_ctx->channels);
+        return AVERROR(EINVAL);
+    }
+
+    av_get_channel_layout_string(buf, sizeof(buf), dec_ctx->channels, chl);
+    av_log(log_ctx, AV_LOG_WARNING,
+           "Channel layout is not set in output stream %d, "
+           "guessed channel layout is '%s'\n",
+           st_index, buf);
+    dec_ctx->channel_layout = chl;
+    return 0;
+}
+
 static av_cold int movie_init(AVFilterContext *ctx, const char *args)
 {
     MovieContext *movie = ctx->priv;
@@ -282,6 +305,12 @@ static av_cold int movie_init(AVFilterContext *ctx, const char *args)
         ret = open_stream(ctx, &movie->st[i]);
         if (ret < 0)
             return ret;
+        if ( movie->st[i].st->codec->codec->type == AVMEDIA_TYPE_AUDIO &&
+            !movie->st[i].st->codec->channel_layout) {
+            ret = guess_channel_layout(&movie->st[i], i, ctx);
+            if (ret < 0)
+                return ret;
+        }
     }
 
     if (!(movie->frame = avcodec_alloc_frame()) ) {
@@ -337,8 +366,7 @@ static int movie_query_formats(AVFilterContext *ctx)
             ff_formats_ref(ff_make_format_list(list), &outlink->in_formats);
             list[0] = c->sample_rate;
             ff_formats_ref(ff_make_format_list(list), &outlink->in_samplerates);
-            list64[0] = c->channel_layout ? c->channel_layout :
-                        av_get_default_channel_layout(c->channels);
+            list64[0] = c->channel_layout;
             ff_channel_layouts_ref(avfilter_make_format64_list(list64),
                                    &outlink->in_channel_layouts);
             break;