[FFmpeg-devel] [PATCHv2] add signature filter for MPEG7 video signature

[Michael Niedermayer]

On Tue, Apr 19, 2016 at 04:37:16PM +0200, Gerion Entrup wrote:
> On Dienstag, 19. April 2016 13:25:53 CEST Moritz Barsnick wrote:
[...]
> +static const ElemCat* elements[ELEMENT_COUNT] = { &elem_a1, &elem_a2,
> +                                                  &elem_d1, &elem_d2, &elem_d3, &elem_d4,
> +                                                  &elem_d5, &elem_d6, &elem_d7, &elem_d8 };
> +
> +// TODO the lut could be here, with calculation at compile time, but don't know how possible
> +//static const int l1distlut[255*256/2];

see

AVOnce


[...]
> +static int request_frame(AVFilterLink *outlink)
> +{
> +    AVFilterContext *ctx = outlink->src;
> +    SignatureContext *sc = ctx->priv;
> +    int i, ret;
> +
> +    for (i = 0; i < sc->nb_inputs; i++){
> +        ret = ff_request_frame(ctx->inputs[i]);
> +        // TODO handle this in a better way?
> +        // Problem is the following:
> +        // Assuming two inputs, inputA with 50 frames, inputB with 100 frames
> +        // simply returning ret when < 0 would result in not filtering inputB
> +        // after 50 frames anymore, not wanted
> +        // only returning ret at the end would result in only respecting the error
> +        // values of the last input, please comment
> +        if (ret < 0 && ret != AVERROR_EOF)
> +            return ret;
> +    }
> +    return ret;
> +}

i dont know what exactly you want to happen when the inputs mismatch
but handling it like other dualinput filters might be an option


[...]
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> +    SignatureContext *sic = ctx->priv;
> +    StreamContext *sc, *sc2;
> +    void* tmp;
> +    FineSignature* finsig;
> +    CourseSignature* cousig;
> +    MatchingInfo match;
> +    int i,j;
> +
> +    //TODO export and especially lookup_signature can have a return value to show some error etc.
> +    //How could this be handled in this function?

why does it need to happen in uninit ?
EOF could be detected before uninit if it doesnt work here


[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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