[FFmpeg-devel] [PATCH 1/2] rtpdec: add fmtp parsing of sprop-maxcapturerate for opus

[Marvin Scholz]

From: Erik Linge <erikli at axis.com>

Co-authored-by: Marvin Scholz <epirat07 at gmail.com>
Signed-off-by: Marvin Scholz <epirat07 at gmail.com>
---
 libavformat/Makefile         |  1 +
 libavformat/rtpdec.c         |  8 +----
 libavformat/rtpdec_formats.h |  1 +
 libavformat/rtpdec_opus.c    | 62 ++++++++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+), 7 deletions(-)
 create mode 100644 libavformat/rtpdec_opus.c

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 6c9992adab..ee68345858 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -62,6 +62,7 @@ OBJS-$(CONFIG_RTPDEC)                    += rdt.o                       \
                                             rtpdec_mpeg12.o             \
                                             rtpdec_mpeg4.o              \
                                             rtpdec_mpegts.o             \
+                                            rtpdec_opus.o               \
                                             rtpdec_qcelp.o              \
                                             rtpdec_qdm2.o               \
                                             rtpdec_qt.o                 \
diff --git a/libavformat/rtpdec.c b/libavformat/rtpdec.c
index a7d5a79a83..10e9502ae2 100644
--- a/libavformat/rtpdec.c
+++ b/libavformat/rtpdec.c
@@ -61,12 +61,6 @@ static const RTPDynamicProtocolHandler speex_dynamic_handler = {
     .codec_id   = AV_CODEC_ID_SPEEX,
 };
 
-static const RTPDynamicProtocolHandler opus_dynamic_handler = {
-    .enc_name   = "opus",
-    .codec_type = AVMEDIA_TYPE_AUDIO,
-    .codec_id   = AV_CODEC_ID_OPUS,
-};
-
 static const RTPDynamicProtocolHandler t140_dynamic_handler = { /* RFC 4103 */
     .enc_name   = "t140",
     .codec_type = AVMEDIA_TYPE_SUBTITLE,
@@ -110,6 +104,7 @@ static const RTPDynamicProtocolHandler *const rtp_dynamic_protocol_handler_list[
     &ff_mpegts_dynamic_handler,
     &ff_ms_rtp_asf_pfa_handler,
     &ff_ms_rtp_asf_pfv_handler,
+    &ff_opus_dynamic_handler,
     &ff_qcelp_dynamic_handler,
     &ff_qdm2_dynamic_handler,
     &ff_qt_rtp_aud_handler,
@@ -125,7 +120,6 @@ static const RTPDynamicProtocolHandler *const rtp_dynamic_protocol_handler_list[
     &ff_vp9_dynamic_handler,
     &gsm_dynamic_handler,
     &l24_dynamic_handler,
-    &opus_dynamic_handler,
     &realmedia_mp3_dynamic_handler,
     &speex_dynamic_handler,
     &t140_dynamic_handler,
diff --git a/libavformat/rtpdec_formats.h b/libavformat/rtpdec_formats.h
index 72a8f16a90..1ff2a72d2a 100644
--- a/libavformat/rtpdec_formats.h
+++ b/libavformat/rtpdec_formats.h
@@ -77,6 +77,7 @@ extern const RTPDynamicProtocolHandler ff_mpeg4_generic_dynamic_handler;
 extern const RTPDynamicProtocolHandler ff_mpegts_dynamic_handler;
 extern const RTPDynamicProtocolHandler ff_ms_rtp_asf_pfa_handler;
 extern const RTPDynamicProtocolHandler ff_ms_rtp_asf_pfv_handler;
+extern const RTPDynamicProtocolHandler ff_opus_dynamic_handler;
 extern const RTPDynamicProtocolHandler ff_qcelp_dynamic_handler;
 extern const RTPDynamicProtocolHandler ff_qdm2_dynamic_handler;
 extern const RTPDynamicProtocolHandler ff_qt_rtp_aud_handler;
diff --git a/libavformat/rtpdec_opus.c b/libavformat/rtpdec_opus.c
new file mode 100644
index 0000000000..60ff2244b6
--- /dev/null
+++ b/libavformat/rtpdec_opus.c
@@ -0,0 +1,62 @@
+/*
+ * RTP OPUS Depacketizer, RFC 7587
+ * Copyright (c) 2022 Erik Linge
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avformat.h"
+#include "rtpdec_formats.h"
+#include "libavutil/avstring.h"
+
+static int parse_fmtp(AVFormatContext *s,
+                           AVStream *stream, PayloadContext *data,
+                           const char *attr, const char *value)
+{
+    if (!strcmp(attr, "sprop-maxcapturerate")) {
+        int rate = atoi(value);
+        if (rate < 8000 || rate > 48000) {
+            av_log(s, AV_LOG_ERROR,
+                "fmtp field 'sprop-maxcapturerate' must be between 8000 to 48000 (provided value: %s)",
+                value);
+            return AVERROR_INVALIDDATA;
+        }
+        stream->codecpar->sample_rate = rate;
+    }
+    return 0;
+}
+
+static int opus_parse_sdp_line(AVFormatContext *s, int st_index,
+                               PayloadContext *data, const char *line)
+{
+    const char *p;
+
+    if (st_index < 0)
+        return 0;
+
+    if (av_strstart(line, "fmtp:", &p)) {
+        return ff_parse_fmtp(s, s->streams[st_index], data, p, parse_fmtp);
+    }
+    return 0;
+}
+
+const RTPDynamicProtocolHandler ff_opus_dynamic_handler = {
+    .enc_name         = "opus",
+    .codec_type       = AVMEDIA_TYPE_AUDIO,
+    .codec_id         = AV_CODEC_ID_OPUS,
+    .parse_sdp_a_line = opus_parse_sdp_line,
+};
-- 
2.39.5 (Apple Git-154)