Justin Ruggles <[email protected]> writes: > On 04/16/2011 09:24 AM, Justin Ruggles wrote: > >> On 04/16/2011 08:59 AM, Måns Rullgård wrote: >> >>> Justin Ruggles <[email protected]> writes: >>> >>>> --- >>>> This patch will also need a change to ff_ac3_extract_exponents_neon(). >>>> Mans, >>>> could you help me out with that? >>>> >>>> -Justin >>>> >>>> libavcodec/ac3dsp.c | 4 +++- >>>> 1 files changed, 3 insertions(+), 1 deletions(-) >>>> >>>> >>>> diff --git a/libavcodec/ac3dsp.c b/libavcodec/ac3dsp.c >>>> index dccad3b..e3ca37e 100644 >>>> --- a/libavcodec/ac3dsp.c >>>> +++ b/libavcodec/ac3dsp.c >>>> @@ -164,8 +164,10 @@ static void ac3_extract_exponents_c(uint8_t *exp, >>>> int32_t *coef, int nb_coefs) >>>> if (e >= 24) { >>>> e = 24; >>>> coef[i] = 0; >>>> + } else if (e < 0) { >>>> + e = 0; >>>> + coef[i] = av_clip(coef[i], -16777215, 16777215); >>>> } >>>> - av_assert2(e >= 0); >>>> } >>>> exp[i] = e; >>>> } >>> >>> Does some other change you have planned make this condition possible? I >>> assume from the assert() that it was impossible before. >> >> >> Well, I don't think it is impossible currently. If either the input >> samples or the MDCT coefficients are outside of [-1.0,1.0] the scaling >> will put it out of the exponent range. Even if the scaled coefficients >> are 25-bit signed, the low value will generate an exponent of -1. > > Also, if an application sends incorrectly-scaled floating point samples, > the encoder will silently generate bad output unless the asserts are > turned on.
I don't really care if invalid input causes bad output. >> This function will also be used for coupling coordinates, and in that >> case they can definitely be out-of-range unless they're clipped prior to >> this. The coordinates are a ratio of 1 channel to the sum of multiple >> channels, divided by 8. So if the ratio is >8 (rare but definitely >> possible) the coordinate will need to be clipped to the valid range at >> some point. OK, then the patch looks good. I'll have to fix the neon code of course. -- Måns Rullgård [email protected] _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
