On 04/16/2011 09:52 AM, Måns Rullgård wrote: > 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.
Should I go ahead and apply it or wait for the neon code? I have the channel coupling patch ready to send, pending approval of all the patches I sent yesterday. It will definitely require that this clipping functionality be in place for all platforms before committing. -Justin _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
