[FFmpeg-devel] [PATCH] lavfi: check the validity of formats lists.

[Andreas Rheinhardt]

Nicolas George:
> Part of the code expect valid lists, in particular no duplicates.

Which part of the code fails if there are duplicates?
ff_merge_channel_layouts() can be easily fixed by adding breaks to all
loops, so if it is only this, we could forgo checking as its cost is
quadratic in the number of elements.

> These tests allow to catch bugs in filters (unlikely but possible)
> and to give a clear message when the error comes from the user
> ((a)formats) or the application (buffersink).
> 
> Signed-off-by: Nicolas George <george at nsup.org>
> ---
>  libavfilter/avfiltergraph.c | 50 ++++++++++++++++++++++++++
>  libavfilter/formats.c       | 71 +++++++++++++++++++++++++++++++++++++
>  libavfilter/formats.h       | 28 +++++++++++++++
>  3 files changed, 149 insertions(+)
> 
> diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
> index c8a52b1f47..b9c7669417 100644
> --- a/libavfilter/avfiltergraph.c
> +++ b/libavfilter/avfiltergraph.c
> @@ -313,6 +313,53 @@ static void sanitize_channel_layouts(void *log, AVFilterChannelLayouts *l)
>      }
>  }
>  
> +static int filter_link_check_formats(void *log, AVFilterLink *link, AVFilterFormatsConfig *cfg)
> +{
> +    int ret;
> +
> +    switch (link->type) {
> +
> +        case AVMEDIA_TYPE_VIDEO:
> +            if ((ret = ff_formats_check_pixel_formats(log, cfg->formats)) < 0)
> +                return ret;
> +            break;
> +
> +        case AVMEDIA_TYPE_AUDIO:
> +            if ((ret = ff_formats_check_sample_formats(log, cfg->formats)) < 0 ||
> +                (ret = ff_formats_check_sample_rates(log, cfg->samplerates)) < 0 ||
> +                (ret = ff_formats_check_channel_layouts(log, cfg->channel_layouts)) < 0)
> +                return ret;
> +            break;
> +
> +        default:
> +            av_assert0(!"reached");
> +    }
> +    return 0;
> +}
> +
> +/**
> + * Check the validity of the formats / etc. lists set by query_formats().
> + *
> + * In particular, check they do not contain any redundant element.
> + */
> +static int filter_check_formats(AVFilterContext *ctx)
> +{
> +    unsigned i;
> +    int ret;
> +
> +    for (i = 0; i < ctx->nb_inputs; i++) {
> +        ret = filter_link_check_formats(ctx, ctx->inputs[i], &ctx->inputs[i]->outcfg);
> +        if (ret < 0)
> +            return ret;
> +    }
> +    for (i = 0; i < ctx->nb_outputs; i++) {
> +        ret = filter_link_check_formats(ctx, ctx->outputs[i], &ctx->outputs[i]->incfg);
> +        if (ret < 0)
> +            return ret;
> +    }
> +    return 0;
> +}
> +
>  static int filter_query_formats(AVFilterContext *ctx)
>  {
>      int ret, i;
> @@ -329,6 +376,9 @@ static int filter_query_formats(AVFilterContext *ctx)
>                     ctx->name, av_err2str(ret));
>          return ret;
>      }
> +    ret = filter_check_formats(ctx);
> +    if (ret < 0)
> +        return ret;
>  
>      for (i = 0; i < ctx->nb_inputs; i++)
>          sanitize_channel_layouts(ctx, ctx->inputs[i]->outcfg.channel_layouts);
> diff --git a/libavfilter/formats.c b/libavfilter/formats.c
> index 8843200f47..fb32874fb6 100644
> --- a/libavfilter/formats.c
> +++ b/libavfilter/formats.c
> @@ -723,3 +723,74 @@ int ff_parse_channel_layout(int64_t *ret, int *nret, const char *arg,
>  
>      return 0;
>  }
> +
> +static int check_list(void *log, const char *name, const AVFilterFormats *fmts)
> +{
> +    unsigned i, j;
> +
> +    if (!fmts)
> +        return 0;
> +    if (!fmts->nb_formats) {
> +        av_log(log, AV_LOG_ERROR, "Empty %s list\n", name);
> +        return AVERROR(EINVAL);
> +    }
> +    for (i = 0; i < fmts->nb_formats; i++) {
> +        for (j = i + 1; j < fmts->nb_formats; j++) {
> +            if (fmts->formats[i] == fmts->formats[j]) {
> +                av_log(log, AV_LOG_ERROR, "Duplicated %s\n", name);
> +                return AVERROR(EINVAL);
> +            }
> +        }
> +    }
> +    return 0;
> +}
> +
> +int ff_formats_check_pixel_formats(void *log, const AVFilterFormats *fmts)
> +{
> +    return check_list(log, "pixel format", fmts);
> +}
> +
> +int ff_formats_check_sample_formats(void *log, const AVFilterFormats *fmts)
> +{
> +    return check_list(log, "sample format", fmts);
> +}
> +
> +int ff_formats_check_sample_rates(void *log, const AVFilterFormats *fmts)
> +{
> +    if (!fmts || !fmts->nb_formats)
> +        return 0;
> +    return check_list(log, "sample rate", fmts);
> +}
> +
> +static int layouts_compatible(uint64_t a, uint64_t b)
> +{
> +    return a == b ||
> +           (KNOWN(a) && !KNOWN(b) && av_get_channel_layout_nb_channels(a) == FF_LAYOUT2COUNT(b)) ||
> +           (KNOWN(b) && !KNOWN(a) && av_get_channel_layout_nb_channels(b) == FF_LAYOUT2COUNT(a));
> +}
> +
> +int ff_formats_check_channel_layouts(void *log, const AVFilterChannelLayouts *fmts)
> +{
> +    unsigned i, j;
> +
> +    if (!fmts)
> +        return 0;
> +    if (fmts->all_layouts < fmts->all_counts ||
> +        (!fmts->all_layouts && !fmts->nb_channel_layouts)) {

This check doesn't fit to the error message and it also makes the next
check below dead code.

> +        av_log(log, AV_LOG_ERROR, "Inconsistent generic list\n");
> +        return AVERROR(EINVAL);
> +    }
> +    if (!fmts->all_layouts && !fmts->nb_channel_layouts) {
> +        av_log(log, AV_LOG_ERROR, "Empty channel layout list\n");
> +        return AVERROR(EINVAL);
> +    }
> +    for (i = 0; i < fmts->nb_channel_layouts; i++) {
> +        for (j = i + 1; j < fmts->nb_channel_layouts; j++) {
> +            if (layouts_compatible(fmts->channel_layouts[i], fmts->channel_layouts[j])) {
> +                av_log(log, AV_LOG_ERROR, "Duplicated or redundant channel layout\n");
> +                return AVERROR(EINVAL);
> +            }
> +        }
> +    }
> +    return 0;
> +}
> diff --git a/libavfilter/formats.h b/libavfilter/formats.h
> index ffe7a12d53..40fb2caa85 100644
> --- a/libavfilter/formats.h
> +++ b/libavfilter/formats.h
> @@ -295,4 +295,32 @@ void ff_formats_unref(AVFilterFormats **ref);
>   */
>  void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref);
>  
> +/**
> + * Check that fmts is a valid pixel formats list.
> + *
> + * In particular, check for duplicates.
> + */
> +int ff_formats_check_pixel_formats(void *log, const AVFilterFormats *fmts);
> +
> +/**
> + * Check that fmts is a valid sample formats list.
> + *
> + * In particular, check for duplicates.
> + */
> +int ff_formats_check_sample_formats(void *log, const AVFilterFormats *fmts);
> +
> +/**
> + * Check that fmts is a valid sample rates list.
> + *
> + * In particular, check for duplicates.
> + */
> +int ff_formats_check_sample_rates(void *log, const AVFilterFormats *fmts);
> +
> +/**
> + * Check that fmts is a valid channel layouts list.
> + *
> + * In particular, check for duplicates.
> + */
> +int ff_formats_check_channel_layouts(void *log, const AVFilterChannelLayouts *fmts);
> +
>  #endif /* AVFILTER_FORMATS_H */
>