[FFmpeg-devel] [PATCH] Various libmpeghdec patches (PR #20602)

[mkver via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #20602 opened by mkver
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20602
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20602.patch

There is another issue not fixed in this PR: The decoder treats avctx->sample_rate as time base of avpkt->pts, although it is AVCodecContext.pkt_timebase. That is probably the reason for the sample_rate check.


>From a4b870ecb2c422faa8bb9fb5876b3a83f5ec4918 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:07:28 +0200
Subject: [PATCH 1/8] avcodec/libmpeghdec: Remove redundant manual close calls

This decoder has the INIT_CLEANUP flag set.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index e293ec3396..ae85924625 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -171,16 +171,13 @@ static av_cold int mpegh3dadec_init(AVCodecContext *avctx)
 
     s->decoder_buffer_size = MAX_OUTBUF_SIZE;
     s->decoder_buffer = av_malloc(s->decoder_buffer_size);
-    if (!s->decoder_buffer) {
-        mpegh3dadec_close(avctx);
+    if (!s->decoder_buffer)
         return AVERROR(ENOMEM);
-    }
 
     // initialize the decoder
     s->decoder = mpeghdecoder_init(cicp);
     if (s->decoder == NULL) {
         av_log(avctx, AV_LOG_ERROR, "MPEG-H decoder library init failed.\n");
-        mpegh3dadec_close(avctx);
         return AVERROR_EXTERNAL;
     }
 
@@ -188,7 +185,6 @@ static av_cold int mpegh3dadec_init(AVCodecContext *avctx)
         if (mpeghdecoder_setMhaConfig(s->decoder, avctx->extradata,
                                       avctx->extradata_size)) {
             av_log(avctx, AV_LOG_ERROR, "Unable to set MHA configuration\n");
-            mpegh3dadec_close(avctx);
             return AVERROR_INVALIDDATA;
         }
     }
-- 
2.49.1


>From b7ef96c52a8534cd2c00ab4d560cf0aca39bc1d7 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:09:39 +0200
Subject: [PATCH 2/8] avcodec/libmpeghdec: Remove private class

This decoder doesn't have any options.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index ae85924625..2d6798e49e 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -35,7 +35,6 @@
 #include "libavutil/channel_layout.h"
 #include "libavutil/frame.h"
 #include "libavutil/mem.h"
-#include "libavutil/opt.h"
 
 #include "codec_internal.h"
 #include "decode.h"
@@ -45,7 +44,6 @@
 #define MAX_OUTBUF_SIZE (sizeof(int32_t) * 24 * 3072 * (MAX_LOST_FRAMES + 1))
 
 typedef struct MPEGH3DADecContext {
-    AVClass *av_class;
     // pointer to the decoder
     HANDLE_MPEGH_DECODER_CONTEXT decoder;
 
@@ -54,13 +52,6 @@ typedef struct MPEGH3DADecContext {
     int decoder_buffer_size;
 } MPEGH3DADecContext;
 
-// private class definition for ffmpeg
-static const AVClass mpegh3da_class = {
-    .class_name = "MPEG-H 3D Audio Decoder",
-    .item_name = av_default_item_name,
-    .version = LIBAVUTIL_VERSION_INT,
-};
-
 static av_cold int mpegh3dadec_close(AVCodecContext *avctx)
 {
     MPEGH3DADecContext *s = avctx->priv_data;
@@ -268,7 +259,6 @@ static av_cold void mpegh3dadec_flush(AVCodecContext *avctx)
 const FFCodec ff_libmpeghdec_decoder = {
     .p.name = "libmpeghdec",
     CODEC_LONG_NAME("libmpeghdec (MPEG-H 3D Audio)"),
-    .p.priv_class = &mpegh3da_class,
     .p.type = AVMEDIA_TYPE_AUDIO,
     .p.id = AV_CODEC_ID_MPEGH_3D_AUDIO,
     .p.capabilities =
-- 
2.49.1


>From 63a1d668db8922a12b8093115512348836e139d5 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:10:32 +0200
Subject: [PATCH 3/8] avcodec/libmpeghdec: Don't set AVCodec.sample_fmts

It is mostly pointless for decoders (only useful for those
codecs for which a floating-point and a fixed-point decoder
exists).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index 2d6798e49e..e3cb219838 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -268,7 +268,6 @@ const FFCodec ff_libmpeghdec_decoder = {
     FF_CODEC_DECODE_CB(mpegh3dadec_decode_frame),
     .close = mpegh3dadec_close,
     .flush = mpegh3dadec_flush,
-    CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S32),
     .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
     .p.wrapper_name = "libmpeghdec",
 };
-- 
2.49.1


>From 2a6618920c40420b0604fe41546ff88fab4e2473 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:13:16 +0200
Subject: [PATCH 4/8] avcodec/libmpeghdec: Inline constant

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index e3cb219838..5233b36bc3 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -236,7 +236,7 @@ static int mpegh3dadec_decode_frame(AVCodecContext *avctx, AVFrame *frame,
 
     memcpy(frame->extended_data[0], s->decoder_buffer,
            avctx->ch_layout.nb_channels * avctx->frame_size *
-               av_get_bytes_per_sample(avctx->sample_fmt));
+           sizeof(*s->decoder_buffer) /* only AV_SAMPLE_FMT_S32 is supported */);
 
     *got_frame_ptr = 1;
     return ret = avpkt->size;
-- 
2.49.1


>From 76892e05752acab6a9e769478cd07058dd6692c8 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:18:57 +0200
Subject: [PATCH 5/8] avcodec/libmpeghdec: Don't use too big buffer

The channel count is fixed, so we don't need to allocate
space to hold samples for nonexisting channels.
Also switch to decoder_buffer_size to be samples-based.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index 5233b36bc3..ebb5e54d7b 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -40,8 +40,8 @@
 #include "decode.h"
 
 #define MAX_LOST_FRAMES 2
-// 32-bit int * 22.2 * max framesize * (max delay frames + 1)
-#define MAX_OUTBUF_SIZE (sizeof(int32_t) * 24 * 3072 * (MAX_LOST_FRAMES + 1))
+// max framesize * (max delay frames + 1)
+#define PER_CHANNEL_OUTBUF_SIZE (3072 * (MAX_LOST_FRAMES + 1))
 
 typedef struct MPEGH3DADecContext {
     // pointer to the decoder
@@ -49,7 +49,7 @@ typedef struct MPEGH3DADecContext {
 
     // Internal values
     int32_t *decoder_buffer;
-    int decoder_buffer_size;
+    int decoder_buffer_size; ///< in samples
 } MPEGH3DADecContext;
 
 static av_cold int mpegh3dadec_close(AVCodecContext *avctx)
@@ -160,8 +160,8 @@ static av_cold int mpegh3dadec_init(AVCodecContext *avctx)
     avctx->sample_fmt = AV_SAMPLE_FMT_S32;
     avctx->sample_rate = 48000;
 
-    s->decoder_buffer_size = MAX_OUTBUF_SIZE;
-    s->decoder_buffer = av_malloc(s->decoder_buffer_size);
+    s->decoder_buffer_size = PER_CHANNEL_OUTBUF_SIZE * avctx->ch_layout.nb_channels;
+    s->decoder_buffer = av_malloc_array(s->decoder_buffer_size, sizeof(*s->decoder_buffer));
     if (!s->decoder_buffer)
         return AVERROR(ENOMEM);
 
@@ -214,7 +214,7 @@ static int mpegh3dadec_decode_frame(AVCodecContext *avctx, AVFrame *frame,
     }
 
     err = mpeghdecoder_getSamples(s->decoder, s->decoder_buffer,
-                                  s->decoder_buffer_size / sizeof(int32_t),
+                                  s->decoder_buffer_size,
                                   &out_info);
     if (err == MPEGH_DEC_FEED_DATA) {
         // no frames to produce at the moment
-- 
2.49.1


>From cad21108aa91439c01bc85073808424fbea6e4dd Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 12:22:33 +0200
Subject: [PATCH 6/8] avcodec/libmpeghdec: Remove always-false check

The pointer to the decoder is always set after init has been
called successfully.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index ebb5e54d7b..174fd5da34 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -247,9 +247,6 @@ static av_cold void mpegh3dadec_flush(AVCodecContext *avctx)
     MPEGH_DECODER_ERROR err;
     MPEGH3DADecContext *s = avctx->priv_data;
 
-    if (!s->decoder)
-        return;
-
     err = mpeghdecoder_flush(s->decoder);
 
     if (err != MPEGH_DEC_OK && err != MPEGH_DEC_FEED_DATA)
-- 
2.49.1


>From 523517c4426820164dfaf55ce6c2a57d65bc8915 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 15:00:25 +0200
Subject: [PATCH 7/8] avcodec/libmpeghdec: Align FFCodec initializers

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index 174fd5da34..bd63db8ed6 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -254,17 +254,17 @@ static av_cold void mpegh3dadec_flush(AVCodecContext *avctx)
 }
 
 const FFCodec ff_libmpeghdec_decoder = {
-    .p.name = "libmpeghdec",
+    .p.name         = "libmpeghdec",
     CODEC_LONG_NAME("libmpeghdec (MPEG-H 3D Audio)"),
-    .p.type = AVMEDIA_TYPE_AUDIO,
-    .p.id = AV_CODEC_ID_MPEGH_3D_AUDIO,
-    .p.capabilities =
-        AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_CHANNEL_CONF,
+    .p.type         = AVMEDIA_TYPE_AUDIO,
+    .p.id           = AV_CODEC_ID_MPEGH_3D_AUDIO,
+    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |
+                      AV_CODEC_CAP_CHANNEL_CONF,
+    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
     .priv_data_size = sizeof(MPEGH3DADecContext),
-    .init = mpegh3dadec_init,
+    .init           = mpegh3dadec_init,
     FF_CODEC_DECODE_CB(mpegh3dadec_decode_frame),
-    .close = mpegh3dadec_close,
-    .flush = mpegh3dadec_flush,
-    .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
+    .flush          = mpegh3dadec_flush,
+    .close          = mpegh3dadec_close,
     .p.wrapper_name = "libmpeghdec",
 };
-- 
2.49.1


>From c72e8408c26eda5dd8795d713d9850a1fdd2893b Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 24 Sep 2025 17:05:27 +0200
Subject: [PATCH 8/8] avcodec/libmpeghdec: Don't set AVCodecContext.frame_size

It indicates a constant frame size (in samples); yet the documentation
of the MPEGH_DECODER_OUTPUT_INFO structure says that it
"gives information about the currently decoded audio data"
and makes no guarantees about it being constant.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/libmpeghdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/libmpeghdec.c b/libavcodec/libmpeghdec.c
index bd63db8ed6..527627ba16 100644
--- a/libavcodec/libmpeghdec.c
+++ b/libavcodec/libmpeghdec.c
@@ -225,7 +225,7 @@ static int mpegh3dadec_decode_frame(AVCodecContext *avctx, AVFrame *frame,
         return AVERROR_UNKNOWN;
     }
 
-    frame->nb_samples = avctx->frame_size = out_info.numSamplesPerChannel;
+    frame->nb_samples  = out_info.numSamplesPerChannel;
     frame->sample_rate = avctx->sample_rate = out_info.sampleRate;
     frame->pts = out_info.ticks;
     frame->time_base.num = 1;
@@ -235,7 +235,7 @@ static int mpegh3dadec_decode_frame(AVCodecContext *avctx, AVFrame *frame,
         return ret;
 
     memcpy(frame->extended_data[0], s->decoder_buffer,
-           avctx->ch_layout.nb_channels * avctx->frame_size *
+           avctx->ch_layout.nb_channels * frame->nb_samples *
            sizeof(*s->decoder_buffer) /* only AV_SAMPLE_FMT_S32 is supported */);
 
     *got_frame_ptr = 1;
-- 
2.49.1

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