[vlc-commits] avcodec/encoder: fix fallback to stereo

[Thomas Guillem]

vlc/vlc-3.0 | branch: master | Thomas Guillem <thomas at gllm.fr> | Thu Jan  4 15:15:36 2018 +0100| [c4bcc88ccf9a0e9f82398e2d82ccacfb6a95005f] | committer: Thomas Guillem

avcodec/encoder: fix fallback to stereo

Happens if the codec doesn't support more than 2 channels (like mp3lame).
Also ask for a channel conversion instead of dropping channels.

(cherry picked from commit 024304087c549888ee824b1f03933dbcfa86d114)
Signed-off-by: Thomas Guillem <thomas at gllm.fr>

> http://git.videolan.org/gitweb.cgi/vlc/vlc-3.0.git/?a=commit;h=c4bcc88ccf9a0e9f82398e2d82ccacfb6a95005f
---

 modules/codec/avcodec/encoder.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/modules/codec/avcodec/encoder.c b/modules/codec/avcodec/encoder.c
index 5f2f671c91..4d513bf02b 100644
--- a/modules/codec/avcodec/encoder.c
+++ b/modules/codec/avcodec/encoder.c
@@ -667,9 +667,6 @@ int OpenEncoder( vlc_object_t *p_this )
     }
     else if( p_enc->fmt_in.i_cat == AUDIO_ES )
     {
-        /* work around bug in libmp3lame encoding */
-        if( i_codec_id == AV_CODEC_ID_MP3 && p_enc->fmt_out.audio.i_channels  > 2 )
-            p_enc->fmt_out.audio.i_channels = 2;
         p_context->codec_type  = AVMEDIA_TYPE_AUDIO;
         p_context->sample_fmt  = p_codec->sample_fmts ?
                                     p_codec->sample_fmts[0] :
@@ -892,7 +889,14 @@ errmsg:
         if( p_context->channels > 2 )
         {
             p_context->channels = 2;
-            p_enc->fmt_in.audio.i_channels = 2; // FIXME
+            p_context->channel_layout = channel_mask[p_context->channels][1];
+
+            /* Change fmt_in in order to ask for a channels conversion */
+            p_enc->fmt_in.audio.i_channels =
+            p_enc->fmt_out.audio.i_channels = 2;
+            p_enc->fmt_in.audio.i_physical_channels =
+            p_enc->fmt_out.audio.i_physical_channels = AOUT_CHANS_STEREO;
+            p_sys->i_channels_to_reorder = 0;
             msg_Warn( p_enc, "stereo mode selected (codec limitation)" );
         }