[FFmpeg-devel] [PR] avformat/rtpenc: use unsigned type for ssrc option (PR #22302)

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

PR #22302 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22302
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22302.patch

The ssrc option used AV_OPT_TYPE_INT with range [INT_MIN, INT_MAX],
but the underlying struct field is uint32_t and RFC 3550 defines SSRC
as a 32-bit identifier covering the full [0, UINT32_MAX] range. This
caused ffmpeg to reject any SSRC value above INT_MAX (~2.1 billion),
which is roughly half of all valid values.

The auto-generated fallback path (av_get_random_seed()) already
returns uint32_t and can produce values above INT_MAX, creating an
inconsistency where the automatic path succeeds but the explicit
-ssrc option rejects the same value.

Change the option to AV_OPT_TYPE_UINT with range [0, UINT32_MAX]
to match the field type and allow the full identifier space.

Fixes ticket #9080.

Signed-off-by: Neko Asakura <neko.asakura@outlook.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>


>From fcb7c9cd5cd2257620eaf7a7861238f03b1e6629 Mon Sep 17 00:00:00 2001
From: Neko Asakura <neko.asakura@outlook.com>
Date: Fri, 20 Feb 2026 20:24:08 +0000
Subject: [PATCH] avformat/rtpenc: use unsigned type for ssrc option

The ssrc option used AV_OPT_TYPE_INT with range [INT_MIN, INT_MAX],
but the underlying struct field is uint32_t and RFC 3550 defines SSRC
as a 32-bit identifier covering the full [0, UINT32_MAX] range. This
caused ffmpeg to reject any SSRC value above INT_MAX (~2.1 billion),
which is roughly half of all valid values.

The auto-generated fallback path (av_get_random_seed()) already
returns uint32_t and can produce values above INT_MAX, creating an
inconsistency where the automatic path succeeds but the explicit
-ssrc option rejects the same value.

Change the option to AV_OPT_TYPE_UINT with range [0, UINT32_MAX]
to match the field type and allow the full identifier space.

Fixes ticket #9080.

Signed-off-by: Neko Asakura <neko.asakura@outlook.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/rtpenc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index 3602b081d5..6d8e95f4c3 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -33,7 +33,7 @@
 static const AVOption options[] = {
     FF_RTP_FLAG_OPTS(RTPMuxContext, flags),
     { "payload_type", "Specify RTP payload type", offsetof(RTPMuxContext, payload_type), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, 127, AV_OPT_FLAG_ENCODING_PARAM },
-    { "ssrc", "Stream identifier", offsetof(RTPMuxContext, ssrc), AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
+    { "ssrc", "Stream identifier", offsetof(RTPMuxContext, ssrc), AV_OPT_TYPE_UINT, { .i64 = 0 }, 0, UINT32_MAX, AV_OPT_FLAG_ENCODING_PARAM },
     { "cname", "CNAME to include in RTCP SR packets", offsetof(RTPMuxContext, cname), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
     { "seq", "Starting sequence number", offsetof(RTPMuxContext, seq), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 65535, AV_OPT_FLAG_ENCODING_PARAM },
     { NULL },
-- 
2.52.0

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