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ffmpeg / libavcodec / a64multienc.c @ 2912e87a

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/*
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 * a64 video encoder - multicolor modes
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 * Copyright (c) 2009 Tobias Bindhammer
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * a64 video encoder - multicolor modes
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 */
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#include "a64enc.h"
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#include "a64colors.h"
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#include "a64tables.h"
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#include "elbg.h"
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#include "libavutil/intreadwrite.h"
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#define DITHERSTEPS   8
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#define CHARSET_CHARS 256
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#define INTERLACED    1
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#define CROP_SCREENS  1
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/* gray gradient */
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static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
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/* other possible gradients - to be tested */
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//static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
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//static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
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static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
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{
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    int blockx, blocky, x, y;
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    int luma = 0;
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    int height = FFMIN(avctx->height, C64YRES);
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    int width  = FFMIN(avctx->width , C64XRES);
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    uint8_t *src = p->data[0];
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    for (blocky = 0; blocky < C64YRES; blocky += 8) {
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        for (blockx = 0; blockx < C64XRES; blockx += 8) {
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            for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
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                for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
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                    if(x < width && y < height) {
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                        /* build average over 2 pixels */
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                        luma = (src[(x + 0 + y * p->linesize[0])] +
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                                src[(x + 1 + y * p->linesize[0])]) / 2;
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                        /* write blocks as linear data now so they are suitable for elbg */
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                        dest[0] = luma;
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                    }
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                    dest++;
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                }
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            }
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        }
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    }
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}
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static void render_charset(AVCodecContext *avctx, uint8_t *charset,
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                           uint8_t *colrammap)
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{
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    A64Context *c = avctx->priv_data;
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    uint8_t row1, row2;
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    int charpos, x, y;
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    int a, b;
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    uint8_t pix;
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    int lowdiff, highdiff;
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    int *best_cb = c->mc_best_cb;
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    static uint8_t index1[256];
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    static uint8_t index2[256];
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    static uint8_t dither[256];
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    int i;
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    int distance;
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    /* generate lookup-tables for dither and index before looping */
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    i = 0;
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    for (a=0; a < 256; a++) {
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        if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
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            distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
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            for(b = 0; b <= distance; b++) {
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                  dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
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            }
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            i++;
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        }
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        if(i >= c->mc_pal_size - 1) dither[a] = 0;
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        index1[a] = i;
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        index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
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    }
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    /* and render charset */
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    for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
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        lowdiff  = 0;
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        highdiff = 0;
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        for (y = 0; y < 8; y++) {
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            row1 = 0; row2 = 0;
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            for (x = 0; x < 4; x++) {
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                pix = best_cb[y * 4 + x];
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                /* accumulate error for brightest/darkest color */
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                if (index1[pix] >= 3)
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                    highdiff += pix - c->mc_luma_vals[3];
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                if (index1[pix] < 1)
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                    lowdiff += c->mc_luma_vals[1] - pix;
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                row1 <<= 2;
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                if (INTERLACED) {
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                    row2 <<= 2;
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                    if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
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                        row1 |= 3-(index2[pix] & 3);
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                    else
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                        row1 |= 3-(index1[pix] & 3);
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                    if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
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                        row2 |= 3-(index2[pix] & 3);
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                    else
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                        row2 |= 3-(index1[pix] & 3);
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                }
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                else {
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                    if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
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                        row1 |= 3-(index2[pix] & 3);
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                    else
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                        row1 |= 3-(index1[pix] & 3);
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                }
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            }
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            charset[y+0x000] = row1;
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            if (INTERLACED) charset[y+0x800] = row2;
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        }
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        /* do we need to adjust pixels? */
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        if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
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            if (lowdiff > highdiff) {
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                for (x = 0; x < 32; x++)
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                    best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
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            } else {
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                for (x = 0; x < 32; x++)
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                    best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
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            }
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            charpos--;          /* redo now adjusted char */
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        /* no adjustment needed, all fine */
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        } else {
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            /* advance pointers */
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            best_cb += 32;
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            charset += 8;
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            /* remember colorram value */
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            colrammap[charpos] = (highdiff > 0);
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        }
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    }
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}
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static av_cold int a64multi_close_encoder(AVCodecContext *avctx)
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{
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    A64Context *c = avctx->priv_data;
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    av_free(c->mc_meta_charset);
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    av_free(c->mc_best_cb);
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    av_free(c->mc_charset);
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    av_free(c->mc_charmap);
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    av_free(c->mc_colram);
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    return 0;
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}
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static av_cold int a64multi_init_encoder(AVCodecContext *avctx)
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{
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    A64Context *c = avctx->priv_data;
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    int a;
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    av_lfg_init(&c->randctx, 1);
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    if (avctx->global_quality < 1) {
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        c->mc_lifetime = 4;
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    } else {
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        c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
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    }
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    av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
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    c->mc_frame_counter = 0;
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    c->mc_use_5col      = avctx->codec->id == CODEC_ID_A64_MULTI5;
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    c->mc_pal_size      = 4 + c->mc_use_5col;
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    /* precalc luma values for later use */
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    for (a = 0; a < c->mc_pal_size; a++) {
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        c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
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                           a64_palette[mc_colors[a]][1] * 0.59 +
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                           a64_palette[mc_colors[a]][2] * 0.11;
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    }
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    if (!(c->mc_meta_charset = av_malloc(32000 * c->mc_lifetime * sizeof(int))) ||
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       !(c->mc_best_cb       = av_malloc(CHARSET_CHARS * 32 * sizeof(int)))     ||
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       !(c->mc_charmap       = av_mallocz(1000 * c->mc_lifetime * sizeof(int))) ||
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       !(c->mc_colram        = av_mallocz(CHARSET_CHARS * sizeof(uint8_t)))     ||
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       !(c->mc_charset       = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {
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        av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
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        return AVERROR(ENOMEM);
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    }
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    /* set up extradata */
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    if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {
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        av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
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        return AVERROR(ENOMEM);
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    }
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    avctx->extradata_size = 8 * 4;
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    AV_WB32(avctx->extradata, c->mc_lifetime);
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    AV_WB32(avctx->extradata + 16, INTERLACED);
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    avcodec_get_frame_defaults(&c->picture);
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    avctx->coded_frame            = &c->picture;
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    avctx->coded_frame->pict_type = FF_I_TYPE;
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    avctx->coded_frame->key_frame = 1;
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    if (!avctx->codec_tag)
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         avctx->codec_tag = AV_RL32("a64m");
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    return 0;
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}
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static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
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{
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    int a;
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    uint8_t temp;
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    /* only needs to be done in 5col mode */
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    /* XXX could be squeezed to 0x80 bytes */
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    for (a = 0; a < 256; a++) {
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        temp  = colram[charmap[a + 0x000]] << 0;
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        temp |= colram[charmap[a + 0x100]] << 1;
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        temp |= colram[charmap[a + 0x200]] << 2;
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        if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
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        buf[a] = temp << 2;
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    }
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}
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static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,
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                                 int buf_size, void *data)
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{
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    A64Context *c = avctx->priv_data;
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    AVFrame *pict = data;
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    AVFrame *const p = (AVFrame *) & c->picture;
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    int frame;
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    int x, y;
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    int b_height;
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    int b_width;
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    int req_size;
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    int num_frames   = c->mc_lifetime;
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    int *charmap     = c->mc_charmap;
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    uint8_t *colram  = c->mc_colram;
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    uint8_t *charset = c->mc_charset;
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    int *meta        = c->mc_meta_charset;
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    int *best_cb     = c->mc_best_cb;
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    int charset_size = 0x800 * (INTERLACED + 1);
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    int colram_size  = 0x100 * c->mc_use_5col;
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    int screen_size;
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    if(CROP_SCREENS) {
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        b_height = FFMIN(avctx->height,C64YRES) >> 3;
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        b_width  = FFMIN(avctx->width ,C64XRES) >> 3;
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        screen_size = b_width * b_height;
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    } else {
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        b_height = C64YRES >> 3;
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        b_width  = C64XRES >> 3;
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        screen_size = 0x400;
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    }
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    /* no data, means end encoding asap */
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    if (!data) {
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        /* all done, end encoding */
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        if (!c->mc_lifetime) return 0;
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        /* no more frames in queue, prepare to flush remaining frames */
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        if (!c->mc_frame_counter) {
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            num_frames = c->mc_lifetime;
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            c->mc_lifetime = 0;
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        }
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        /* still frames in queue so limit lifetime to remaining frames */
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        else c->mc_lifetime = c->mc_frame_counter;
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    /* still new data available */
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    } else {
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        /* fill up mc_meta_charset with data until lifetime exceeds */
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        if (c->mc_frame_counter < c->mc_lifetime) {
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            *p = *pict;
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            p->pict_type = FF_I_TYPE;
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            p->key_frame = 1;
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            to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
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            c->mc_frame_counter++;
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            /* lifetime is not reached so wait for next frame first */
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            return 0;
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        }
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    }
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    /* lifetime reached so now convert X frames at once */
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    if (c->mc_frame_counter == c->mc_lifetime) {
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        req_size = 0;
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        /* any frames to encode? */
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        if (c->mc_lifetime) {
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            /* calc optimal new charset + charmaps */
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            ff_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
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            ff_do_elbg  (meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
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            /* create colorram map and a c64 readable charset */
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            render_charset(avctx, charset, colram);
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            /* copy charset to buf */
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            memcpy(buf,charset, charset_size);
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            /* advance pointers */
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            buf      += charset_size;
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            charset  += charset_size;
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            req_size += charset_size;
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        }
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        /* no charset so clean buf */
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        else memset(buf, 0, charset_size);
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        /* write x frames to buf */
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        for (frame = 0; frame < c->mc_lifetime; frame++) {
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            /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */
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            for (y = 0; y < b_height; y++) {
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                for (x = 0; x < b_width; x++) {
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                    buf[y * b_width + x] = charmap[y * b_width + x];
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                }
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            }
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            /* advance pointers */
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            buf += screen_size;
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            req_size += screen_size;
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            /* compress and copy colram to buf */
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            if (c->mc_use_5col) {
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                a64_compress_colram(buf, charmap, colram);
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                /* advance pointers */
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                buf += colram_size;
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                req_size += colram_size;
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            }
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            /* advance to next charmap */
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            charmap += 1000;
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        }
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        AV_WB32(avctx->extradata + 4,  c->mc_frame_counter);
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        AV_WB32(avctx->extradata + 8,  charset_size);
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        AV_WB32(avctx->extradata + 12, screen_size + colram_size);
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        /* reset counter */
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        c->mc_frame_counter = 0;
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        if (req_size > buf_size) {
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            av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", req_size, buf_size);
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            return -1;
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        }
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        return req_size;
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    }
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    return 0;
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}
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AVCodec ff_a64multi_encoder = {
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    .name           = "a64multi",
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = CODEC_ID_A64_MULTI,
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    .priv_data_size = sizeof(A64Context),
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    .init           = a64multi_init_encoder,
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    .encode         = a64multi_encode_frame,
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    .close          = a64multi_close_encoder,
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    .pix_fmts       = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},
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    .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
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    .capabilities   = CODEC_CAP_DELAY,
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};
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AVCodec ff_a64multi5_encoder = {
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    .name           = "a64multi5",
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    .type           = AVMEDIA_TYPE_VIDEO,
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    .id             = CODEC_ID_A64_MULTI5,
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    .priv_data_size = sizeof(A64Context),
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    .init           = a64multi_init_encoder,
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    .encode         = a64multi_encode_frame,
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    .close          = a64multi_close_encoder,
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    .pix_fmts       = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},
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    .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
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    .capabilities   = CODEC_CAP_DELAY,
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};