On 2025-01-10 12:10 +0200, Martin Storsjö wrote:
> On Wed, 8 Jan 2025, j...@jonb.org wrote:
>
> > From: Jonathan Baudanza <j...@jonb.org>
> >
> > This was previously adjusted by me in 6b3f9c2e92b.
> > Unfortunately, I traded one integer overflow bug for
> > another.
> >
> > Currently, NTP timestamps that exceed INT64_MAX
> > (~Jan 20, 1968) will cause an overflow when passed
> > to av_rescale.
> >
> > This patch replaces av_rescale, which operates on
> > int64_t, with ff_parse_ntp_time, which operates on
> > uint64_t. This will give the correct values for
> > timestamps back around the NTP epoch and present day
> > timestamps.
> > ---
> > libavformat/rtsp.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
> > index c48fa26d90..5ea471b40c 100644
> > --- a/libavformat/rtsp.c
> > +++ b/libavformat/rtsp.c
> > @@ -2320,7 +2320,7 @@ redo:
> > }
> > // Make real NTP start time available in AVFormatContext
> > if (s->start_time_realtime == AV_NOPTS_VALUE) {
> > - s->start_time_realtime = av_rescale
> > (rtpctx->first_rtcp_ntp_time, 1000000, 1LL << 32) - NTP_OFFSET_US;
> > + s->start_time_realtime =
> > ff_parse_ntp_time(rtpctx->first_rtcp_ntp_time) - NTP_OFFSET_US;
> > if (rtpctx->st) {
> > s->start_time_realtime -=
> > av_rescale_q (rtpctx->rtcp_ts_offset,
> > rtpctx->st->time_base, AV_TIME_BASE_Q);
> > --
> > 2.41.0
>
> Looks ok - I've managed to reproduce this now.
>
> I'll apply this, and backport it to the 7.1 branch.
Thanks Martin!
FTR: I could also reproduce and confirm the fix locally.
Alexander
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