[FFmpeg-devel] [PATCH] lavc: add channels field to AVFrame

[Stefano Sabatini]

This is required otherwise it is not always possible to guess the number
of channels from the layout, for example if the channel layout is
unknown.
---
 libavcodec/avcodec.h |   11 +++++++++++
 libavcodec/utils.c   |    4 ++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index edbc59b..fb16c83 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1337,6 +1337,15 @@ typedef struct AVFrame {
     int decode_error_flags;
 #define FF_DECODE_ERROR_INVALID_BITSTREAM   1
 #define FF_DECODE_ERROR_MISSING_REFERENCE   2
+
+    /**
+     * number of audio channels, only used for audio.
+     * Code outside libavcodec should access this field using:
+     * av_frame_get_channels(frame)
+     * - encoding: unused
+     * - decoding: Read by user.
+     */
+    int64_t channels;
 } AVFrame;
 
 /**
@@ -1352,6 +1361,8 @@ int64_t av_frame_get_pkt_pos              (const AVFrame *frame);
 void    av_frame_set_pkt_pos              (AVFrame *frame, int64_t val);
 int64_t av_frame_get_channel_layout       (const AVFrame *frame);
 void    av_frame_set_channel_layout       (AVFrame *frame, int64_t val);
+int     av_frame_get_channels             (const AVFrame *frame);
+void    av_frame_set_channels             (AVFrame *frame, int     val);
 int     av_frame_get_sample_rate          (const AVFrame *frame);
 void    av_frame_set_sample_rate          (AVFrame *frame, int     val);
 AVDictionary *av_frame_get_metadata       (const AVFrame *frame);
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 53fda1f..2f4cb5d 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -427,6 +427,7 @@ static int audio_get_buffer(AVCodecContext *avctx, AVFrame *frame)
     frame->sample_rate    = avctx->sample_rate;
     frame->format         = avctx->sample_fmt;
     frame->channel_layout = avctx->channel_layout;
+    frame->channels       = avctx->channels;
 
     if (avctx->debug & FF_DEBUG_BUFFERS)
         av_log(avctx, AV_LOG_DEBUG, "default_get_buffer called on frame %p, "
@@ -724,6 +725,7 @@ MAKE_ACCESSORS(AVFrame, frame, int64_t, best_effort_timestamp)
 MAKE_ACCESSORS(AVFrame, frame, int64_t, pkt_duration)
 MAKE_ACCESSORS(AVFrame, frame, int64_t, pkt_pos)
 MAKE_ACCESSORS(AVFrame, frame, int64_t, channel_layout)
+MAKE_ACCESSORS(AVFrame, frame, int,     channels)
 MAKE_ACCESSORS(AVFrame, frame, int,     sample_rate)
 MAKE_ACCESSORS(AVFrame, frame, AVDictionary *, metadata)
 MAKE_ACCESSORS(AVFrame, frame, int,     decode_error_flags)
@@ -1648,6 +1650,8 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
                 frame->format = avctx->sample_fmt;
             if (!frame->channel_layout)
                 frame->channel_layout = avctx->channel_layout;
+            if (!frame->channels)
+                frame->channels = avctx->channels;
             if (!frame->sample_rate)
                 frame->sample_rate = avctx->sample_rate;
         }
-- 
1.7.5.4