On 27.12.2015 21:13, Hendrik Leppkes wrote: > On Sun, Dec 27, 2015 at 9:03 PM, Andreas Cadhalpun > <andreas.cadhal...@googlemail.com> wrote: >> On 27.12.2015 20:43, Hendrik Leppkes wrote: >>> On Sun, Dec 27, 2015 at 8:29 PM, Andreas Cadhalpun >>> <andreas.cadhal...@googlemail.com> wrote: >>>> On 27.12.2015 20:10, Hendrik Leppkes wrote: >>>>> Invalid timebases have a zero numerator, not denominator. >>>> >>>> A timebase with zero numerator is probably invalid, but a timebase >>>> with zero denominator is not even well defined. >>>> So this comment doesn't seem quite right. >>>> >>>>> Fixes a integer divison by zero. >>>>> --- >>>>> libavcodec/utils.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/libavcodec/utils.c b/libavcodec/utils.c >>>>> index 19f3f0a..33295ed 100644 >>>>> --- a/libavcodec/utils.c >>>>> +++ b/libavcodec/utils.c >>>>> @@ -2435,7 +2435,7 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, >>>>> AVSubtitle *sub, >>>>> } else { >>>>> avctx->internal->pkt = &pkt_recoded; >>>>> >>>>> - if (avctx->pkt_timebase.den && avpkt->pts != AV_NOPTS_VALUE) >>>>> + if (avctx->pkt_timebase.num && avpkt->pts != AV_NOPTS_VALUE) >>>>> sub->pts = av_rescale_q(avpkt->pts, >>>>> avctx->pkt_timebase, >>>>> AV_TIME_BASE_Q); >>>>> ret = avctx->codec->decode(avctx, sub, got_sub_ptr, >>>>> &pkt_recoded); >>>>> >>>> >>>> If avctx->pkt_timebase.den is 0, calling av_rescale_q here will trigger the >>>> av_assert2(c > 0) in av_rescale_rnd, so removing this check isn't good. >>>> >>>> Why not check for both num and den? >>>> >>> >>> We never check both, invalid timebase is {0, 1}, anything else needs >>> to have values in both. >> >> I'd call this unknown timebase, as {0, 1} is the initialization value. >> A {1, 0} timebase is certainly not valid. >> >>> All timebase checks are for num only. >> >> The check here was for den and there is a similar check in >> teletext_decode_frame. > > And thats a bug since that can actually lead to div by 0 and crash.
Then please fix this bug also in teletext_decode_frame. > The same timebase is checked 5 lines down for num already. Indeed. Best regards, Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel