From acc30ec0fa4a9b1d91e318923200241321b02f58 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Thu, 12 Dec 2024 12:25:56 -0400
Subject: [PATCH] MT#55283 amend resample_frame() semantics

In many transcoding scenarios resampling is not actually required. We
can shortcut the operation by just returning the original frame, instead
of a cloned and newly allocated one. We just need to distinguish between
the cases to determine whether the frame returned by resample_frame()
needs to be freed.

Change-Id: I3f36a46bd3b967f140c8353119fdb24ad8363c15
---
 daemon/codec.c             | 3 ++-
 lib/codeclib.c             | 6 ++++--
 lib/resample.c             | 2 +-
 recording-daemon/decoder.c | 8 ++++++--
 recording-daemon/mix.c     | 3 ++-
 5 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/daemon/codec.c b/daemon/codec.c
index 6ea60b464..d0034d83c 100644
--- a/daemon/codec.c
+++ b/daemon/codec.c
@@ -4180,7 +4180,8 @@ static void __dtmf_detect(struct codec_ssrc_handler *ch, AVFrame *frame) {
 		num_samples = ret;
 	}
 	ch->dtmf_ts = dsp_frame->pts + dsp_frame->nb_samples;
-	av_frame_free(&dsp_frame);
+	if (dsp_frame != frame)
+		av_frame_free(&dsp_frame);
 }
 
 static int packet_decoded_common(decoder_t *decoder, AVFrame *frame, void *u1, void *u2,
diff --git a/lib/codeclib.c b/lib/codeclib.c
index 06ecdae1c..7b932105a 100644
--- a/lib/codeclib.c
+++ b/lib/codeclib.c
@@ -1238,7 +1238,8 @@ static int __decoder_input_data(decoder_t *dec, const str *data, unsigned long t
 			if (callback(dec, rsmp_frame, u1, u2))
 				ret = -1;
 		}
-		av_frame_free(&frame);
+		if (rsmp_frame != frame)
+			av_frame_free(&frame);
 	}
 
 	if (ptime)
@@ -2158,7 +2159,8 @@ int encoder_input_fifo(encoder_t *enc, AVFrame *frame,
 	}
 	if (av_audio_fifo_write(enc->fifo, (void **) rsmp_frame->extended_data, rsmp_frame->nb_samples) < 0)
 		return -1;
-	av_frame_free(&rsmp_frame);
+	if (rsmp_frame != frame)
+		av_frame_free(&rsmp_frame);
 
 	return encoder_fifo_flush(enc, callback, u1, u2);
 }
diff --git a/lib/resample.c b/lib/resample.c
index 8fbc58022..16f07378c 100644
--- a/lib/resample.c
+++ b/lib/resample.c
@@ -31,7 +31,7 @@ AVFrame *resample_frame(resample_t *resample, AVFrame *frame, const format_t *to
 	if (!CH_LAYOUT_EQ(frame->CH_LAYOUT, to_channel_layout))
 		goto resample;
 
-	return av_frame_clone(frame);
+	return frame;
 
 resample:
 
diff --git a/recording-daemon/decoder.c b/recording-daemon/decoder.c
index a4ba07d91..ab1cc228e 100644
--- a/recording-daemon/decoder.c
+++ b/recording-daemon/decoder.c
@@ -121,13 +121,16 @@ static int decoder_got_frame(decoder_t *dec, AVFrame *frame, void *sp, void *dp)
 			goto no_mix_out;
 		mix_config(metafile->mix, &actual_format);
 		// XXX might be a second resampling to same format
-		AVFrame *dec_frame = resample_frame(&deco->mix_resampler, frame, &actual_format);
+		AVFrame *copy_frame = av_frame_clone(frame);
+		AVFrame *dec_frame = resample_frame(&deco->mix_resampler, copy_frame, &actual_format);
 		if (!dec_frame) {
 			pthread_mutex_unlock(&metafile->mix_lock);
 			goto err;
 		}
 		if (mix_add(metafile->mix, dec_frame, deco->mixer_idx, ssrc, metafile->mix_out))
 			ilog(LOG_ERR, "Failed to add decoded packet to mixed output");
+		if (dec_frame != copy_frame)
+			av_frame_free(&copy_frame);
 	}
 no_mix_out:
 	pthread_mutex_unlock(&metafile->mix_lock);
@@ -183,7 +186,8 @@ no_recording:
 		int linesize = av_get_bytes_per_sample(dec_frame->format) * dec_frame->nb_samples;
 		dbg("Writing %u bytes PCM to TLS", linesize);
 		streambuf_write(ssrc->tls_fwd_stream, (char *) dec_frame->extended_data[0], linesize);
-		av_frame_free(&dec_frame);
+		if (dec_frame != frame)
+			av_frame_free(&dec_frame);
 
 	}
 
diff --git a/recording-daemon/mix.c b/recording-daemon/mix.c
index c50f9364d..6f79d5231 100644
--- a/recording-daemon/mix.c
+++ b/recording-daemon/mix.c
@@ -393,7 +393,8 @@ int mix_add(mix_t *mix, AVFrame *frame, unsigned int idx, void *ptr, output_t *o
 		ret = output_add(output, frame);
 
 		av_frame_unref(mix->sink_frame);
-		av_frame_free(&frame);
+		if (frame != mix->sink_frame)
+			av_frame_free(&frame);
 
 		if (ret)
 			return -1;