[FFmpeg-devel] [PATCH] avformat/rtp: Pass sources and block filter addresses via sdp file for rtp

[Ross Nicholson]

Ok, latest patch uses AVBPrint. Please let me know if my usage is correct,
I have not used it before.

In the meantime I will get some users to test this.

On Mon, 6 Apr 2020 at 20:57, Marton Balint <cus at passwd.hu> wrote:

>
>
> On Mon, 6 Apr 2020, phunkyfish wrote:
>
> > ---
> > libavformat/rtsp.c | 47 ++++++++++++++++++++++++++++++++++++++--------
> > 1 file changed, 39 insertions(+), 8 deletions(-)
> >
> > diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
> > index cd6fc32a29..0d0bc2be0d 100644
> > --- a/libavformat/rtsp.c
> > +++ b/libavformat/rtsp.c
> > @@ -2447,8 +2447,8 @@ static int rtp_probe(const AVProbeData *p)
> > static int rtp_read_header(AVFormatContext *s)
> > {
> >     uint8_t recvbuf[RTP_MAX_PACKET_LENGTH];
> > -    char host[500], sdp[500];
> > -    int ret, port;
> > +    char host[500], sdp[1000], filters_buf[1000];
> > +    int ret, port, sdp_length, nc;
> >     URLContext* in = NULL;
> >     int payload_type;
> >     AVCodecParameters *par = NULL;
> > @@ -2456,6 +2456,7 @@ static int rtp_read_header(AVFormatContext *s)
> >     AVIOContext pb;
> >     socklen_t addrlen = sizeof(addr);
> >     RTSPState *rt = s->priv_data;
> > +    const char *p;
> >
> >     if (!ff_network_init())
> >         return AVERROR(EIO);
> > @@ -2513,13 +2514,40 @@ static int rtp_read_header(AVFormatContext *s)
> >     av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port,
> >                  NULL, 0, s->url);
> >
> > -    snprintf(sdp, sizeof(sdp),
> > -             "v=0\r\nc=IN IP%d %s\r\nm=%s %d RTP/AVP %d\r\n",
> > -             addr.ss_family == AF_INET ? 4 : 6, host,
> > -             par->codec_type == AVMEDIA_TYPE_DATA  ? "application" :
> > -             par->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio",
> > -             port, payload_type);
> > +    sdp_length = snprintf(sdp, sizeof(sdp),
> > +                          "v=0\r\nc=IN IP%d %s\r\n",
> > +                          addr.ss_family == AF_INET ? 4 : 6, host);
>
> Please use an AVBPrint buffer instead of snprintf()-ing to sdp.
>
> Thanks,
> Marton
>
> > +
> > +    p = strchr(s->url, '?');
> > +    if (p) {
> > +        static const char *filters[][2] = {{"sources", "incl"},
> {"block", "excl"}, {NULL, NULL}};
> > +        int i;
> > +        char *q;
> > +        for (i = 0; filters[i][0]; i++) {
> > +            if (av_find_info_tag(filters_buf, sizeof(filters_buf),
> filters[i][0], p)) {
> > +                q = filters_buf;
> > +                while ((q = strchr(q, ',')) != NULL)
> > +                    *q = ' ';
> > +                nc = snprintf(sdp + sdp_length, sizeof(sdp) -
> sdp_length,
> > +                              "a=source-filter:%s IN IP%d %s %s\r\n",
> > +                              filters[i][1],
> > +                              addr.ss_family == AF_INET ? 4 : 6, host,
> > +                              filters_buf);
> > +                if (nc < 0 || nc + sdp_length >= sizeof(sdp))
> > +                    goto fail_nobuf;
> > +                sdp_length += nc;
> > +            }
> > +        }
> > +    }
> > +
> > +    nc = snprintf(sdp + sdp_length, sizeof(sdp) - sdp_length,
> > +                  "m=%s %d RTP/AVP %d\r\n",
> > +                  par->codec_type == AVMEDIA_TYPE_DATA  ? "application"
> :
> > +                  par->codec_type == AVMEDIA_TYPE_VIDEO ? "video" :
> "audio",
> > +                  port, payload_type);
> >     av_log(s, AV_LOG_VERBOSE, "SDP:\n%s\n", sdp);
> > +    if (nc < 0 || nc + sdp_length >= sizeof(sdp))
> > +        goto fail_nobuf;
> >     avcodec_parameters_free(&par);
> >
> >     ffio_init_context(&pb, sdp, strlen(sdp), 0, NULL, NULL, NULL, NULL);
> > @@ -2534,6 +2562,9 @@ static int rtp_read_header(AVFormatContext *s)
> >     s->pb = NULL;
> >     return ret;
> >
> > +fail_nobuf:
> > +    ret = AVERROR(ENOBUFS);
> > +    av_log(s, AV_LOG_ERROR, "rtp_read_header(): not enough buffer space
> for sdp-headers\n");
> > fail:
> >     avcodec_parameters_free(&par);
> >     if (in)
> > --
> > 2.24.1 (Apple Git-126)
> >
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