[FFmpeg-devel] [PATCH v2 1/3] avfilter: add v360 filter

[Thilo Borgmann]

[...]

>>> +static int config_output(AVFilterLink *outlink)
>>> +{
>>> +    AVFilterContext *ctx = outlink->src;
>>> +    AVFilterLink *inlink = ctx->inputs[0];
>>> +    V360Context *s = ctx->priv;
>>> +    const AVPixFmtDescriptor *desc =
>>> av_pix_fmt_desc_get(inlink->format);
>>> +    const int depth = desc->comp[0].depth;
>>> +    float remap_data_size = 0.f;
>>> +    int sizeof_remap;
>>> +    int err;
>>> +    int p, h, w;
>>> +    float hf, wf;
>>> +    float mirror_modifier[3];
>>> +    void (*in_transform)(const V360Context *s,
>>> +                         const float *vec, int width, int height,
>>> +                         uint16_t us[4][4], uint16_t vs[4][4], float
>>> *du, float *dv);
>>> +    void (*out_transform)(const V360Context *s,
>>> +                          int i, int j, int width, int height,
>>> +                          float *vec);
>>> +    void (*calculate_kernel)(float du, float dv, int shift, const
>> XYRemap4
>>> *r_tmp, void *r);
>>> +    float rot_mat[3][3];
>>> +
>>> +    switch (s->interp) {
>>> +    case NEAREST:
>>> +        calculate_kernel = nearest_kernel;
>>> +        s->remap_slice = depth <= 8 ? remap1_8bit_slice :
>>> remap1_16bit_slice;
>>> +        sizeof_remap = sizeof(XYRemap1);
>>> +        break;
>>> +    case BILINEAR:
>>> +        calculate_kernel = bilinear_kernel;
>>> +        s->remap_slice = depth <= 8 ? remap2_8bit_slice :
>>> remap2_16bit_slice;
>>> +        sizeof_remap = sizeof(XYRemap2);
>>> +        break;
>>> +    case BICUBIC:
>>> +        calculate_kernel = bicubic_kernel;
>>> +        s->remap_slice = depth <= 8 ? remap4_8bit_slice :
>>> remap4_16bit_slice;
>>> +        sizeof_remap = sizeof(XYRemap4);
>>> +        break;
>>> +    case LANCZOS:
>>> +        calculate_kernel = lanczos_kernel;
>>> +        s->remap_slice = depth <= 8 ? remap4_8bit_slice :
>>> remap4_16bit_slice;
>>> +        sizeof_remap = sizeof(XYRemap4);
>>> +        break;
>>> +    }
>>> +
>>> +    switch (s->in) {
>>> +    case EQUIRECTANGULAR:
>>> +        in_transform = xyz_to_equirect;
>>> +        err = 0;
>>> +        wf = inlink->w;
>>> +        hf = inlink->h;
>>> +        break;
>>> +    case CUBEMAP_3_2:
>>> +        in_transform = xyz_to_cube3x2;
>>> +        err = prepare_cube_in(ctx);
>>> +        wf = inlink->w / 3.f * 4.f;
>>> +        hf = inlink->h;
>>> +        break;
>>> +    case CUBEMAP_6_1:
>>> +        in_transform = xyz_to_cube6x1;
>>> +        err = prepare_cube_in(ctx);
>>> +        wf = inlink->w / 3.f * 2.f;
>>> +        hf = inlink->h * 2.f;
>>> +        break;
>>> +    case EQUIANGULAR:
>>> +        in_transform = xyz_to_eac;
>>> +        err = prepare_eac_in(ctx);
>>> +        wf = inlink->w;
>>> +        hf = inlink->h / 9.f * 8.f;
>>> +        break;
>>> +    case FLAT:
>>> +        av_log(ctx, AV_LOG_ERROR, "Flat format is not accepted as
>>> input.\n");
>>> +        return AVERROR(EINVAL);
>>> +    }
>>> +
>>> +    if (err != 0) {
>>> +        return err;
>>> +    }
>>> +
>>> +    switch (s->out) {
>>> +    case EQUIRECTANGULAR:
>>> +        out_transform = equirect_to_xyz;
>>> +        err = 0;
>>> +        w = roundf(wf);
>>> +        h = roundf(hf);
>>> +        break;
>>> +    case CUBEMAP_3_2:
>>> +        out_transform = cube3x2_to_xyz;
>>> +        err = prepare_cube_out(ctx);
>>> +        w = roundf(wf / 4.f * 3.f);
>>> +        h = roundf(hf);
>>> +        break;
>>> +    case CUBEMAP_6_1:
>>> +        out_transform = cube6x1_to_xyz;
>>> +        err = prepare_cube_out(ctx);
>>> +        w = roundf(wf / 2.f * 3.f);
>>> +        h = roundf(hf / 2.f);
>>> +        break;
>>> +    case EQUIANGULAR:
>>> +        out_transform = eac_to_xyz;
>>> +        err = prepare_eac_out(ctx);
>>> +        w = roundf(wf);
>>> +        h = roundf(hf / 8.f * 9.f);
>>> +        break;
>>> +    case FLAT:
>>> +        out_transform = flat_to_xyz;
>>> +        err = prepare_flat_out(ctx);
>>> +        w = roundf(wf * s->flat_range[0] / s->flat_range[1] / 2.f);
>>> +        h = roundf(hf);
>>> +        break;
>>> +    }
>>> +
>>> +    if (err != 0) {
>>> +        return err;
>>> +    }
>>> +
>>> +    if (s->width > 0 && s->height > 0) {
>>> +        w = s->width;
>>> +        h = s->height;
>>> +    }
>>
>> If s->width/height are checked, should handle the case of no ture,
>> Else w/h may be used but not initialized.
>>
> 
> Please try more hard to write english. I do not understand what is typed
> above.

If w and h don't have initial values at declaration. So they might never get set if that last if statement evaluates to false.

So he suggests to add an else case like

if (s->width > 0 && s->height > 0) {
 w = s->width;
 h = s->height;
} else {
 w = 0;
 h = 0;
}

or whatever values might make sense.

Thilo