PeerStreamer

/*

 * a64 video encoder - multicolor modes

 * Copyright (c) 2009 Tobias Bindhammer

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * a64 video encoder - multicolor modes

 */

#include "a64enc.h"

#include "a64colors.h"

#include "a64tables.h"

#include "elbg.h"

#include "libavutil/intreadwrite.h"

#define DITHERSTEPS   8

#define CHARSET_CHARS 256

#define INTERLACED    1

#define CROP_SCREENS  1

/* gray gradient */

static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};

/* other possible gradients - to be tested */

//static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};

//static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};

static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)

{

    int blockx, blocky, x, y;

    int luma = 0;

    int height = FFMIN(avctx->height, C64YRES);

    int width  = FFMIN(avctx->width , C64XRES);

    uint8_t *src = p->data[0];

    for (blocky = 0; blocky < C64YRES; blocky += 8) {

        for (blockx = 0; blockx < C64XRES; blockx += 8) {

            for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {

                for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {

                    if(x < width && y < height) {

                        /* build average over 2 pixels */

                        luma = (src[(x + 0 + y * p->linesize[0])] +

                                src[(x + 1 + y * p->linesize[0])]) / 2;

                        /* write blocks as linear data now so they are suitable for elbg */

                        dest[0] = luma;

                    }

                    dest++;

                }

            }

        }

    }

}

static void render_charset(AVCodecContext *avctx, uint8_t *charset,

                           uint8_t *colrammap)

{

    A64Context *c = avctx->priv_data;

    uint8_t row1, row2;

    int charpos, x, y;

    int a, b;

    uint8_t pix;

    int lowdiff, highdiff;

    int *best_cb = c->mc_best_cb;

    static uint8_t index1[256];

    static uint8_t index2[256];

    static uint8_t dither[256];

    int i;

    int distance;

    /* generate lookup-tables for dither and index before looping */

    i = 0;

    for (a=0; a < 256; a++) {

        if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {

            distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];

            for(b = 0; b <= distance; b++) {

                  dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;

            }

            i++;

        }

        if(i >= c->mc_pal_size - 1) dither[a] = 0;

        index1[a] = i;

        index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);

    }

    /* and render charset */

    for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {

        lowdiff  = 0;

        highdiff = 0;

        for (y = 0; y < 8; y++) {

            row1 = 0; row2 = 0;

            for (x = 0; x < 4; x++) {

                pix = best_cb[y * 4 + x];

                /* accumulate error for brightest/darkest color */

                if (index1[pix] >= 3)

                    highdiff += pix - c->mc_luma_vals[3];

                if (index1[pix] < 1)

                    lowdiff += c->mc_luma_vals[1] - pix;

                row1 <<= 2;

                if (INTERLACED) {

                    row2 <<= 2;

                    if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])

                        row1 |= 3-(index2[pix] & 3);

                    else

                        row1 |= 3-(index1[pix] & 3);

                    if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])

                        row2 |= 3-(index2[pix] & 3);

                    else

                        row2 |= 3-(index1[pix] & 3);

                }

                else {

                    if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])

                        row1 |= 3-(index2[pix] & 3);

                    else

                        row1 |= 3-(index1[pix] & 3);

                }

            }

            charset[y+0x000] = row1;

            if (INTERLACED) charset[y+0x800] = row2;

        }

        /* do we need to adjust pixels? */

        if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {

            if (lowdiff > highdiff) {

                for (x = 0; x < 32; x++)

                    best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);

            } else {

                for (x = 0; x < 32; x++)

                    best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);

            }

            charpos--;          /* redo now adjusted char */

        /* no adjustment needed, all fine */

        } else {

            /* advance pointers */

            best_cb += 32;

            charset += 8;

            /* remember colorram value */

            colrammap[charpos] = (highdiff > 0);

        }

    }

}

static av_cold int a64multi_close_encoder(AVCodecContext *avctx)

{

    A64Context *c = avctx->priv_data;

    av_free(c->mc_meta_charset);

    av_free(c->mc_best_cb);

    av_free(c->mc_charset);

    av_free(c->mc_charmap);

    av_free(c->mc_colram);

    return 0;

}

static av_cold int a64multi_init_encoder(AVCodecContext *avctx)

{

    A64Context *c = avctx->priv_data;

    int a;

    av_lfg_init(&c->randctx, 1);

    if (avctx->global_quality < 1) {

        c->mc_lifetime = 4;

    } else {

        c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;

    }

    av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);

    c->mc_frame_counter = 0;

    c->mc_use_5col      = avctx->codec->id == CODEC_ID_A64_MULTI5;

    c->mc_pal_size      = 4 + c->mc_use_5col;

    /* precalc luma values for later use */

    for (a = 0; a < c->mc_pal_size; a++) {

        c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +

                           a64_palette[mc_colors[a]][1] * 0.59 +

                           a64_palette[mc_colors[a]][2] * 0.11;

    }

    if (!(c->mc_meta_charset = av_malloc(32000 * c->mc_lifetime * sizeof(int))) ||

       !(c->mc_best_cb       = av_malloc(CHARSET_CHARS * 32 * sizeof(int)))     ||

       !(c->mc_charmap       = av_mallocz(1000 * c->mc_lifetime * sizeof(int))) ||

       !(c->mc_colram        = av_mallocz(CHARSET_CHARS * sizeof(uint8_t)))     ||

       !(c->mc_charset       = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {

        av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");

        return AVERROR(ENOMEM);

    }

    /* set up extradata */

    if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {

        av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");

        return AVERROR(ENOMEM);

    }

    avctx->extradata_size = 8 * 4;

    AV_WB32(avctx->extradata, c->mc_lifetime);

    AV_WB32(avctx->extradata + 16, INTERLACED);

    avcodec_get_frame_defaults(&c->picture);

    avctx->coded_frame            = &c->picture;

    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;

    avctx->coded_frame->key_frame = 1;

    if (!avctx->codec_tag)

         avctx->codec_tag = AV_RL32("a64m");

    return 0;

}

static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)

{

    int a;

    uint8_t temp;

    /* only needs to be done in 5col mode */

    /* XXX could be squeezed to 0x80 bytes */

    for (a = 0; a < 256; a++) {

        temp  = colram[charmap[a + 0x000]] << 0;

        temp |= colram[charmap[a + 0x100]] << 1;

        temp |= colram[charmap[a + 0x200]] << 2;

        if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;

        buf[a] = temp << 2;

    }

}

static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,

                                 int buf_size, void *data)

{

    A64Context *c = avctx->priv_data;

    AVFrame *pict = data;

    AVFrame *const p = (AVFrame *) & c->picture;

    int frame;

    int x, y;

    int b_height;

    int b_width;

    int req_size;

    int num_frames   = c->mc_lifetime;

    int *charmap     = c->mc_charmap;

    uint8_t *colram  = c->mc_colram;

    uint8_t *charset = c->mc_charset;

    int *meta        = c->mc_meta_charset;

    int *best_cb     = c->mc_best_cb;

    int charset_size = 0x800 * (INTERLACED + 1);

    int colram_size  = 0x100 * c->mc_use_5col;

    int screen_size;

    if(CROP_SCREENS) {

        b_height = FFMIN(avctx->height,C64YRES) >> 3;

        b_width  = FFMIN(avctx->width ,C64XRES) >> 3;

        screen_size = b_width * b_height;

    } else {

        b_height = C64YRES >> 3;

        b_width  = C64XRES >> 3;

        screen_size = 0x400;

    }

    /* no data, means end encoding asap */

    if (!data) {

        /* all done, end encoding */

        if (!c->mc_lifetime) return 0;

        /* no more frames in queue, prepare to flush remaining frames */

        if (!c->mc_frame_counter) {

            num_frames = c->mc_lifetime;

            c->mc_lifetime = 0;

        }

        /* still frames in queue so limit lifetime to remaining frames */

        else c->mc_lifetime = c->mc_frame_counter;

    /* still new data available */

    } else {

        /* fill up mc_meta_charset with data until lifetime exceeds */

        if (c->mc_frame_counter < c->mc_lifetime) {

            *p = *pict;

            p->pict_type = AV_PICTURE_TYPE_I;

            p->key_frame = 1;

            to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);

            c->mc_frame_counter++;

            /* lifetime is not reached so wait for next frame first */

            return 0;

        }

    }

    /* lifetime reached so now convert X frames at once */

    if (c->mc_frame_counter == c->mc_lifetime) {

        req_size = 0;

        /* any frames to encode? */

        if (c->mc_lifetime) {

            /* calc optimal new charset + charmaps */

            ff_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);

            ff_do_elbg  (meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);

            /* create colorram map and a c64 readable charset */

            render_charset(avctx, charset, colram);

            /* copy charset to buf */

            memcpy(buf,charset, charset_size);

            /* advance pointers */

            buf      += charset_size;

            charset  += charset_size;

            req_size += charset_size;

        }

        /* no charset so clean buf */

        else memset(buf, 0, charset_size);

        /* write x frames to buf */

        for (frame = 0; frame < c->mc_lifetime; frame++) {

            /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */

            for (y = 0; y < b_height; y++) {

                for (x = 0; x < b_width; x++) {

                    buf[y * b_width + x] = charmap[y * b_width + x];

                }

            }

            /* advance pointers */

            buf += screen_size;

            req_size += screen_size;

            /* compress and copy colram to buf */

            if (c->mc_use_5col) {

                a64_compress_colram(buf, charmap, colram);

                /* advance pointers */

                buf += colram_size;

                req_size += colram_size;

            }

            /* advance to next charmap */

            charmap += 1000;

        }

        AV_WB32(avctx->extradata + 4,  c->mc_frame_counter);

        AV_WB32(avctx->extradata + 8,  charset_size);

        AV_WB32(avctx->extradata + 12, screen_size + colram_size);

        /* reset counter */

        c->mc_frame_counter = 0;

        if (req_size > buf_size) {

            av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", req_size, buf_size);

            return -1;

        }

        return req_size;

    }

    return 0;

}

AVCodec ff_a64multi_encoder = {

    .name           = "a64multi",

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = CODEC_ID_A64_MULTI,

    .priv_data_size = sizeof(A64Context),

    .init           = a64multi_init_encoder,

    .encode         = a64multi_encode_frame,

    .close          = a64multi_close_encoder,

    .pix_fmts       = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},

    .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),

    .capabilities   = CODEC_CAP_DELAY,

};

AVCodec ff_a64multi5_encoder = {

    .name           = "a64multi5",

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = CODEC_ID_A64_MULTI5,

    .priv_data_size = sizeof(A64Context),

    .init           = a64multi_init_encoder,

    .encode         = a64multi_encode_frame,

    .close          = a64multi_close_encoder,

    .pix_fmts       = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},

    .long_name      = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),

    .capabilities   = CODEC_CAP_DELAY,

};