static void swap_sample_fmts_on_filter(AVFilterContext *filter) { AVFilterLink *link = NULL; int format, bps; int i, j; for (i = 0; i < filter->nb_inputs; i++) { link = filter->inputs[i]; if (link->type == AVMEDIA_TYPE_AUDIO && link->out_formats->format_count == 1) break; } if (i == filter->nb_inputs) return; format = link->out_formats->formats[0]; bps = av_get_bytes_per_sample(format); for (i = 0; i < filter->nb_outputs; i++) { AVFilterLink *outlink = filter->outputs[i]; int best_idx, best_score = INT_MIN; if (outlink->type != AVMEDIA_TYPE_AUDIO || outlink->in_formats->format_count < 2) continue; for (j = 0; j < outlink->in_formats->format_count; j++) { int out_format = outlink->in_formats->formats[j]; int out_bps = av_get_bytes_per_sample(out_format); int score; if (av_get_packed_sample_fmt(out_format) == format || av_get_planar_sample_fmt(out_format) == format) { best_idx = j; break; } /* for s32 and float prefer double to prevent loss of information */ if (bps == 4 && out_bps == 8) { best_idx = j; break; } /* prefer closest higher or equal bps */ score = -abs(out_bps - bps); if (out_bps >= bps) score += INT_MAX/2; if (score > best_score) { best_score = score; best_idx = j; } } FFSWAP(int, outlink->in_formats->formats[0], outlink->in_formats->formats[best_idx]); } }