[FFmpeg-devel,PATCHv2,2/2] avfilter/ebur128: fix relative threshold calculation for multiple contexts

This reworks the code a bit and also disallows NULL contexts.

Fixes Coverity CID 1396273, 1396279.

Signed-off-by: Marton Balint <cus@passwd.hu>
---
 libavfilter/ebur128.c | 46 ++++++++++++++++------------------------------
 1 file changed, 16 insertions(+), 30 deletions(-)

On Sat, 4 Feb 2017, Marton Balint wrote:

> This reworks the code a bit and also disallows NULL contexts.
>
> Fixes Coverity CID 1396273, 1396279.
>
> Signed-off-by: Marton Balint <cus@passwd.hu>
> ---
> libavfilter/ebur128.c | 46 ++++++++++++++++------------------------------
> 1 file changed, 16 insertions(+), 30 deletions(-)
>
> diff --git a/libavfilter/ebur128.c b/libavfilter/ebur128.c
> index 012df54..e110080 100644
> --- a/libavfilter/ebur128.c
> +++ b/libavfilter/ebur128.c
> @@ -519,26 +519,27 @@ FF_EBUR128_ADD_FRAMES(int)
> FF_EBUR128_ADD_FRAMES(float)
> FF_EBUR128_ADD_FRAMES(double)
> 
> -static int ebur128_calc_relative_threshold(FFEBUR128State * st,
> -                                           size_t * above_thresh_counter,
> +static int ebur128_calc_relative_threshold(FFEBUR128State **sts, size_t size,
>                                            double *relative_threshold)
> {
> -    size_t i;
> +    size_t i, j;
> +    int above_thresh_counter = 0;
>     *relative_threshold = 0.0;
> -    *above_thresh_counter = 0;
> 
> -    for (i = 0; i < 1000; ++i) {
> -        *relative_threshold += st->d->block_energy_histogram[i] *
> -            histogram_energies[i];
> -        *above_thresh_counter += st->d->block_energy_histogram[i];
> +    for (i = 0; i < size; i++) {
> +        unsigned long *block_energy_histogram = sts[i]->d->block_energy_histogram;
> +        for (j = 0; j < 1000; ++j) {
> +            *relative_threshold += block_energy_histogram[j] * histogram_energies[j];
> +            above_thresh_counter += block_energy_histogram[j];
> +        }
>     }
> 
> -    if (*above_thresh_counter != 0) {
> -        *relative_threshold /= (double) *above_thresh_counter;
> +    if (above_thresh_counter != 0) {
> +        *relative_threshold /= (double)above_thresh_counter;
>         *relative_threshold *= RELATIVE_GATE_FACTOR;
>     }
> 
> -    return 0;
> +    return above_thresh_counter;
> }
> 
> static int ebur128_gated_loudness(FFEBUR128State ** sts, size_t size,
> @@ -549,20 +550,11 @@ static int ebur128_gated_loudness(FFEBUR128State ** sts, size_t size,
>     size_t above_thresh_counter;
>     size_t i, j, start_index;
> 
> -    for (i = 0; i < size; i++) {
> -        if (sts[i]
> -            && (sts[i]->mode & FF_EBUR128_MODE_I) != FF_EBUR128_MODE_I) {
> +    for (i = 0; i < size; i++)
> +        if ((sts[i]->mode & FF_EBUR128_MODE_I) != FF_EBUR128_MODE_I)
>             return AVERROR(EINVAL);
> -        }
> -    }
> 
> -    for (i = 0; i < size; i++) {
> -        if (!sts[i])
> -            continue;
> -        ebur128_calc_relative_threshold(sts[i], &above_thresh_counter,
> -                                        &relative_threshold);
> -    }
> -    if (!above_thresh_counter) {
> +    if (!ebur128_calc_relative_threshold(sts, size, &relative_threshold)) {
>         *out = -HUGE_VAL;
>         return 0;
>     }
> @@ -577,8 +569,6 @@ static int ebur128_gated_loudness(FFEBUR128State ** sts, size_t size,
>         }
>     }
>     for (i = 0; i < size; i++) {
> -        if (!sts[i])
> -            continue;
>         for (j = start_index; j < 1000; ++j) {
>             gated_loudness += sts[i]->d->block_energy_histogram[j] *
>                 histogram_energies[j];
> @@ -597,15 +587,11 @@ static int ebur128_gated_loudness(FFEBUR128State ** sts, size_t size,
> int ff_ebur128_relative_threshold(FFEBUR128State * st, double *out)
> {
>     double relative_threshold;
> -    size_t above_thresh_counter;
>
>     if ((st->mode & FF_EBUR128_MODE_I) != FF_EBUR128_MODE_I)
>         return AVERROR(EINVAL);
> 
> -    ebur128_calc_relative_threshold(st, &above_thresh_counter,
> -                                    &relative_threshold);
> -
> -    if (!above_thresh_counter) {
> +    if (!ebur128_calc_relative_threshold(&st, 1, &relative_threshold)) {
>         *out = -70.0;
>         return 0;
>     }
> -- 
> 2.10.2

Pushed the series.

Regards,
Marton