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

[Thilo Borgmann]

Am 14.08.19 um 15:14 schrieb Eugene:
> On 14.08.2019 13:06, Paul B Mahol wrote:
> 
>> On Wed, Aug 14, 2019 at 11:56 AM Thilo Borgmann <thilo.borgmann at mail.de>
>> wrote:
>>
>>> [...]
>>>
>>>>>> +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.
>>>
>> else case should have assert or return AVERROR_BUG.
> 
> This "if" branch overrides default values with user values. Default values are calculated just above this code based on input/output formats.
> So w and h do get initialized in any case.

Hmm... what happens if (s->out != any case you have in the switch) and (s->width < 1 || s->height < 1)

Maybe I misread, actually I just clarified what Li Zhong said.

-Thilo