[PR] avcodec/libfdk-aacdec: add support for more height channels (PR #24260)

PR #24260 opened by James Almer (jamrial)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24260
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24260.patch


>From cf2b0693219715e5bb49aab57551646f6c7c27a4 Mon Sep 17 00:00:00 2001
From: James Almer <[email protected]>
Date: Mon, 24 Aug 2026 22:06:52 -0300
Subject: [PATCH 1/2] avcodec/libfdk-aacdec: add support for top back and top
 side channels

While PCE can signal these, libfdk-aac supports only up to 8 channels, so any sample
that could contain these will most likely have more channels than can be decoded anyway.

Signed-off-by: James Almer <[email protected]>
---
 libavcodec/libfdk-aacdec.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/libavcodec/libfdk-aacdec.c b/libavcodec/libfdk-aacdec.c
index d1008e2a36..9aa9ef5e09 100644
--- a/libavcodec/libfdk-aacdec.c
+++ b/libavcodec/libfdk-aacdec.c
@@ -239,6 +239,42 @@ static int get_stream_info(AVCodecContext *avctx, AVFrame *frame)
             break;
         }
     }
+    if (channel_counts[ACT_BACK_TOP] > 0) {
+        switch (channel_counts[ACT_BACK_TOP]) {
+        case 3:
+        case 2:
+            ch_layout |= AV_CH_TOP_BACK_LEFT | AV_CH_TOP_BACK_RIGHT;
+            av_fallthrough;
+        case 1:
+            if (channel_counts[ACT_BACK_TOP] & 1)
+                ch_layout |= AV_CH_TOP_BACK_CENTER;
+            break;
+        default:
+            av_log(avctx, AV_LOG_WARNING,
+                   "unsupported number of top back channels: %d\n",
+                   channel_counts[ACT_BACK_TOP]);
+            ch_error = 1;
+            break;
+        }
+    }
+    if (channel_counts[ACT_SIDE_TOP] > 0) {
+        switch (channel_counts[ACT_SIDE_TOP]) {
+        case 3:
+        case 2:
+            ch_layout |= AV_CH_TOP_SIDE_LEFT | AV_CH_TOP_SIDE_RIGHT;
+            av_fallthrough;
+        case 1:
+            if (channel_counts[ACT_SIDE_TOP] & 1)
+                ch_layout |= AV_CH_TOP_CENTER;
+            break;
+        default:
+            av_log(avctx, AV_LOG_WARNING,
+                   "unsupported number of top side channels: %d\n",
+                   channel_counts[ACT_SIDE_TOP]);
+            ch_error = 1;
+            break;
+        }
+    }
 
     av_channel_layout_uninit(&avctx->ch_layout);
     av_channel_layout_from_mask(&avctx->ch_layout, ch_layout);
-- 
2.52.0


>From 9dfcf1a2eb212bea727030b89d8fb544dff34c15 Mon Sep 17 00:00:00 2001
From: James Almer <[email protected]>
Date: Mon, 24 Aug 2026 23:05:57 -0300
Subject: [PATCH 2/2] avcodec/libfdk-aacdec: add support for bottom front
 channels

Same as the previous commit, actual samples with less than eight channels including
these is very unlikely.

Signed-off-by: James Almer <[email protected]>
---
 libavcodec/libfdk-aacdec.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/libavcodec/libfdk-aacdec.c b/libavcodec/libfdk-aacdec.c
index 9aa9ef5e09..41ff4887a6 100644
--- a/libavcodec/libfdk-aacdec.c
+++ b/libavcodec/libfdk-aacdec.c
@@ -151,12 +151,14 @@ static int get_stream_info(AVCodecContext *avctx, AVFrame *frame)
         channel_counts[ctype]++;
     }
     av_log(avctx, AV_LOG_DEBUG,
-           "%d channels - front:%d side:%d back:%d lfe:%d top:%d\n",
+           "%d channels - front:%d side:%d back:%d lfe:%d top:%d bottom %d\n",
            info->numChannels,
            channel_counts[ACT_FRONT], channel_counts[ACT_SIDE],
            channel_counts[ACT_BACK],  channel_counts[ACT_LFE],
            channel_counts[ACT_FRONT_TOP] + channel_counts[ACT_SIDE_TOP] +
-           channel_counts[ACT_BACK_TOP]  + channel_counts[ACT_TOP]);
+           channel_counts[ACT_BACK_TOP]  + channel_counts[ACT_TOP],
+           channel_counts[ACT_FRONT_BOTTOM] + channel_counts[ACT_SIDE_BOTTOM] +
+           channel_counts[ACT_BACK_BOTTOM]  + channel_counts[ACT_BOTTOM]);
 
     switch (channel_counts[ACT_FRONT]) {
     case 5:
@@ -275,6 +277,24 @@ static int get_stream_info(AVCodecContext *avctx, AVFrame *frame)
             break;
         }
     }
+    if (channel_counts[ACT_FRONT_BOTTOM] > 0) {
+        switch (channel_counts[ACT_FRONT_BOTTOM]) {
+        case 3:
+        case 2:
+            ch_layout |= AV_CH_BOTTOM_FRONT_LEFT | AV_CH_BOTTOM_FRONT_RIGHT;
+            av_fallthrough;
+        case 1:
+            if (channel_counts[ACT_FRONT_BOTTOM] & 1)
+                ch_layout |= AV_CH_BOTTOM_FRONT_CENTER;
+            break;
+        default:
+            av_log(avctx, AV_LOG_WARNING,
+                   "unsupported number of bottom front channels: %d\n",
+                   channel_counts[ACT_FRONT_BOTTOM]);
+            ch_error = 1;
+            break;
+        }
+    }
 
     av_channel_layout_uninit(&avctx->ch_layout);
     av_channel_layout_from_mask(&avctx->ch_layout, ch_layout);
-- 
2.52.0

_______________________________________________
ffmpeg-devel mailing list -- [email protected]
To unsubscribe send an email to [email protected]