[FFmpeg-devel] [PATCH v5 3/3] avformat/whip: fix typos

[Jack Lau]

> On Jun 29, 2025, at 19:47, Timo Rothenpieler <timo at rothenpieler.org> wrote:
> 
> On 29.06.2025 05:14, Jack Lau wrote:
>>> On Jun 29, 2025, at 11:11, Jack Lau <jacklau1222gm at gmail.com> wrote:
>>> 
>>> Hi Timo,
>>>> On Jun 29, 2025, at 06:49, Timo Rothenpieler <timo at rothenpieler.org> wrote:
>>>> 
>>>> I've actually cleaned this up a bit while trying to implement DTLS via schannel, and effectively removed the whole section:
>>>> 
>>>>> https://github.com/BtbN/FFmpeg/commit/b6794f1373fb07b791cfacd2189c7efc4d6bdbcc
>>>> 
>>>> There's also a bunch of other necessary UDP related fixes in tls.c.
>>>> 
>>>> Don't try to use an http proxy for UDP. It doesn't work:
>>>>> https://github.com/BtbN/FFmpeg/commit/709ce9e5c48e3a27a400cf5af35038d3f0602c8a
>>> I totally agree with the above two patches, it’s very reasonable
>>>> 
>>>> Properly forward the various hosts and ports to udp.c so it actually works when using a non-external UDP connection:
>>>>> https://github.com/BtbN/FFmpeg/commit/46375adf7d9cc61f709ab14dd2ea017995f735db
>>> But I think this patch need a bit modify, I think the c->listen stands for FFmpeg if is server. When it is true, FFmpeg as server.
>>> So maybe:
>>>         if (c->listen) {
>>>             av_dict_set_int(options, "localport", port, 0);
>>>             av_dict_set(options, "localaddr", c->underlying_host, 0);Add commentMore actions
>>>         } else {
>>>             av_dict_set_int(options, "connect", 1, 0);
>>>         }
>> Sry for forgetting modify this code, the right code I want to express is that:
>>         if (c->listen) {
>>             av_dict_set_int(options, "connect", 1, 0);
>>         } else {
>>             av_dict_set_int(options, "localport", port, 0);
>>             av_dict_set(options, "localaddr", c->underlying_host, 0);
>>         }
> 
> It goes together with
>> https://github.com/BtbN/FFmpeg/commit/6fc902eb75554e6ad91a2ddf4ce1d131feee6f55
> 
> Without setting the localport to 0 in client-mode in combination with above patch, it'll try to bind to the port passed in the URL, which when tryong to connect to a server on localhost will result in a bind failure, cause it tried to bind to the same port.
I also found this issue, I’m not sure modify the udp code if is suitable, but I can provide a workaround:

@@ -127,23 +127,22 @@ int ff_tls_open_underlying(TLSShared *c, URLContext *parent, const char *uri, AV

-    ret = ffurl_open_whitelist(c->is_dtls ? &c->udp : &c->tcp, buf, AVIO_FLAG_READ_WRITE,
+    ret = ffurl_open_whitelist(c->is_dtls ? &c->udp : &c->tcp, buf,
+                               c->is_dtls ? (c->listen ? AVIO_FLAG_READ : AVIO_FLAG_WRITE) : AVIO_FLAG_READ_WRITE,
                                &parent->interrupt_callback, options,
                                parent->protocol_whitelist, parent->protocol_blacklist, parent);
diff --git a/libavformat/tls_openssl.c b/libavformat/tls_openssl.c
index 2a3905891d..9cc5acd3e1 100644
--- a/libavformat/tls_openssl.c
+++ b/libavformat/tls_openssl.c
@@ -985,6 +985,9 @@ static int dtls_start(URLContext *h, const char *url, int flags, AVDictionary **
             av_log(p, AV_LOG_ERROR, "Failed to connect %s\n", url);
             return ret;
         }
+        /* Make the socket non-blocking, set to READ and WRITE mode after connected */
+        ff_socket_nonblock(ffurl_get_file_handle(p->tls_shared.udp), 1);
+        p->tls_shared.udp->flags |= AVIO_FLAG_READ | AVIO_FLAG_WRITE | AVIO_FLAG_NONBLOCK;
     }
 
> 
> And "connect" in listen mode makes no sense to me?
> There is no remote address, where would it "connect" the socket to?
Oops! I got it mixed up.
You’re right.
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