On 09/08/15 23:16, Justin Ruggles wrote:
> On 08/07/2015 06:13 PM, Luca Barbato wrote:
>> Give priority to pixel formats closer to the input.
>> ---
>>
>> I kept it as simple as possible on purpose.
>>
>> libavfilter/avfiltergraph.c | 97
>> +++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 97 insertions(+)
>>
>> diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
>> index 0fc385c..91a9d71 100644
>> --- a/libavfilter/avfiltergraph.c
>> +++ b/libavfilter/avfiltergraph.c
>> @@ -31,6 +31,7 @@
>> #include "libavutil/internal.h"
>> #include "libavutil/log.h"
>> #include "libavutil/opt.h"
>> +#include "libavutil/pixdesc.h"
>>
>> #include "avfilter.h"
>> #include "formats.h"
>> @@ -742,6 +743,100 @@ static int pick_formats(AVFilterGraph *graph)
>> return 0;
>> }
>>
>> +#define same_flag(d1, d2, flag) \
>> + !(!!(d1->flags & flag) ^ !!(d2->flags & flag))
>> +
>> +static int find_best_pix_fmt_match(AVFilterLink *outlink,
>> + const AVPixFmtDescriptor *in_desc,
>> + int in_format)
>> +{
>> + int j;
>> + int best_idx = -1, best_score = INT_MIN;
>> +
>> + for (j = 0; j < outlink->in_formats->nb_formats; j++) {
>> + int format =
>> outlink->in_formats->formats[j];
>> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
>> +
>> + int score;
>> +
>> + int same_alpha = same_flag(desc, in_desc,
>> AV_PIX_FMT_FLAG_ALPHA);
>> + int same_rgb = same_flag(desc, in_desc, AV_PIX_FMT_FLAG_RGB);
>> + int bpc = desc->comp[0].depth_minus1;
>> + int in_bpc = in_desc->comp[0].depth_minus1;
>> +
>> + if (bpc < in_bpc)
>> + score = bpc - in_bpc;
>> + else
>> + score = 0;
>> +
>> + score += -10 * abs(desc->nb_components -
>> + in_desc->nb_components);
>> +
>> + if (same_alpha && same_rgb) {
>> + score += 2;
>> + } else if (desc->flags & AV_PIX_FMT_FLAG_ALPHA) {
>> + if (same_alpha)
>> + score += 1;
>> + } else {
>> + if (same_rgb)
>> + score += 1;
>> + }
>> +
>> + if (score > best_score) {
>> + best_score = score;
>> + best_idx = j;
>> + }
>> + }
>> +
>> + return best_idx;
>> +}
>> +
>> +static void swap_pix_fmts_on_filter(AVFilterContext *filter)
>> +{
>> + AVFilterLink *link = NULL;
>> + const AVPixFmtDescriptor *desc;
>> + int format;
>> + int i;
>> +
>> + for (i = 0; i < filter->nb_inputs; i++) {
>> + link = filter->inputs[i];
>> +
>> + if (link->type == AVMEDIA_TYPE_VIDEO &&
>> + link->out_formats->nb_formats == 1)
>> + break;
>> + }
>> + if (i == filter->nb_inputs)
>> + return;
>> +
>> + format = link->out_formats->formats[0];
>> + desc = av_pix_fmt_desc_get(format);
>> +
>> + for (i = 0; i < filter->nb_outputs; i++) {
>> + AVFilterLink *outlink = filter->outputs[i];
>> + int best_idx;
>> +
>> + if (outlink->type != AVMEDIA_TYPE_VIDEO ||
>> + outlink->in_formats->nb_formats < 2)
>> + continue;
>> +
>> + best_idx = find_best_pix_fmt_match(outlink, desc, format);
>> +
>> + if (best_idx > -1)
>> + FFSWAP(int, outlink->in_formats->formats[0],
>> + outlink->in_formats->formats[best_idx]);
>> + }
>> +}
>
> I'm not so sure I like how the scoring is implemented here. The most
> logical to me would be a strict layered matching. Ideally, my preference
> would be, in order or priority:
>
> - preserve alpha only if the input has alpha
Can be done.
> - preserve average, non-alpha, bit depth
You end up with 16bits gray while 8bits gray is more than enough.
> - preserve colorspace
Ok
> - preserve individual component (including alpha) bit depths, if applicable
Ok, I can extend what I put there, that part seems working quite well.
> - preserve component ordering/packing
>
> Something like this could still be done within a scoring system.
I'll update the rules soon.
lu
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