PeerStreamer

/*

 * Smacker decoder

 * Copyright (c) 2006 Konstantin Shishkov

 *

 * 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 libavcodec/smacker.c

 * Smacker decoder

 */

/*

 * Based on http://wiki.multimedia.cx/index.php?title=Smacker

 */

#include <stdio.h>

#include <stdlib.h>

#include "avcodec.h"

#define ALT_BITSTREAM_READER_LE

#include "get_bits.h"

#include "bytestream.h"

#define SMKTREE_BITS 9

#define SMK_NODE 0x80000000

/*

 * Decoder context

 */

typedef struct SmackVContext {

    AVCodecContext *avctx;

    AVFrame pic;

    int *mmap_tbl, *mclr_tbl, *full_tbl, *type_tbl;

    int mmap_last[3], mclr_last[3], full_last[3], type_last[3];

} SmackVContext;

/**

 * Context used for code reconstructing

 */

typedef struct HuffContext {

    int length;

    int maxlength;

    int current;

    uint32_t *bits;

    int *lengths;

    int *values;

} HuffContext;

/* common parameters used for decode_bigtree */

typedef struct DBCtx {

    VLC *v1, *v2;

    int *recode1, *recode2;

    int escapes[3];

    int *last;

    int lcur;

} DBCtx;

/* possible runs of blocks */

static const int block_runs[64] = {

      1,    2,    3,    4,    5,    6,    7,    8,

      9,   10,   11,   12,   13,   14,   15,   16,

     17,   18,   19,   20,   21,   22,   23,   24,

     25,   26,   27,   28,   29,   30,   31,   32,

     33,   34,   35,   36,   37,   38,   39,   40,

     41,   42,   43,   44,   45,   46,   47,   48,

     49,   50,   51,   52,   53,   54,   55,   56,

     57,   58,   59,  128,  256,  512, 1024, 2048 };

enum SmkBlockTypes {

    SMK_BLK_MONO = 0,

    SMK_BLK_FULL = 1,

    SMK_BLK_SKIP = 2,

    SMK_BLK_FILL = 3 };

/**

 * Decode local frame tree

 */

static int smacker_decode_tree(GetBitContext *gb, HuffContext *hc, uint32_t prefix, int length)

{

    if(!get_bits1(gb)){ //Leaf

        if(hc->current >= 256){

            av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");

            return -1;

        }

        if(length){

            hc->bits[hc->current] = prefix;

            hc->lengths[hc->current] = length;

        } else {

            hc->bits[hc->current] = 0;

            hc->lengths[hc->current] = 0;

        }

        hc->values[hc->current] = get_bits(gb, 8);

        hc->current++;

        if(hc->maxlength < length)

            hc->maxlength = length;

        return 0;

    } else { //Node

        int r;

        length++;

        r = smacker_decode_tree(gb, hc, prefix, length);

        if(r)

            return r;

        return smacker_decode_tree(gb, hc, prefix | (1 << (length - 1)), length);

    }

}

/**

 * Decode header tree

 */

static int smacker_decode_bigtree(GetBitContext *gb, HuffContext *hc, DBCtx *ctx)

{

    if(!get_bits1(gb)){ //Leaf

        int val, i1, i2, b1, b2;

        if(hc->current >= hc->length){

            av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");

            return -1;

        }

        b1 = get_bits_count(gb);

        i1 = get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3);

        b1 = get_bits_count(gb) - b1;

        b2 = get_bits_count(gb);

        i2 = get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3);

        b2 = get_bits_count(gb) - b2;

        val = ctx->recode1[i1] | (ctx->recode2[i2] << 8);

        if(val == ctx->escapes[0]) {

            ctx->last[0] = hc->current;

            val = 0;

        } else if(val == ctx->escapes[1]) {

            ctx->last[1] = hc->current;

            val = 0;

        } else if(val == ctx->escapes[2]) {

            ctx->last[2] = hc->current;

            val = 0;

        }

        hc->values[hc->current++] = val;

        return 1;

    } else { //Node

        int r = 0, t;

        t = hc->current++;

        r = smacker_decode_bigtree(gb, hc, ctx);

        if(r < 0)

            return r;

        hc->values[t] = SMK_NODE | r;

        r++;

        r += smacker_decode_bigtree(gb, hc, ctx);

        return r;

    }

}

/**

 * Store large tree as FFmpeg's vlc codes

 */

static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)

{

    int res;

    HuffContext huff;

    HuffContext tmp1, tmp2;

    VLC vlc[2];

    int escapes[3];

    DBCtx ctx;

    if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow

        av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");

        return -1;

    }

    tmp1.length = 256;

    tmp1.maxlength = 0;

    tmp1.current = 0;

    tmp1.bits = av_mallocz(256 * 4);

    tmp1.lengths = av_mallocz(256 * sizeof(int));

    tmp1.values = av_mallocz(256 * sizeof(int));

    tmp2.length = 256;

    tmp2.maxlength = 0;

    tmp2.current = 0;

    tmp2.bits = av_mallocz(256 * 4);

    tmp2.lengths = av_mallocz(256 * sizeof(int));

    tmp2.values = av_mallocz(256 * sizeof(int));

    memset(&vlc[0], 0, sizeof(VLC));

    memset(&vlc[1], 0, sizeof(VLC));

    if(get_bits1(gb)) {

        smacker_decode_tree(gb, &tmp1, 0, 0);

        skip_bits1(gb);

        res = init_vlc(&vlc[0], SMKTREE_BITS, tmp1.length,

                    tmp1.lengths, sizeof(int), sizeof(int),

                    tmp1.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);

        if(res < 0) {

            av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");

            return -1;

        }

    } else {

        av_log(smk->avctx, AV_LOG_ERROR, "Skipping low bytes tree\n");

    }

    if(get_bits1(gb)){

        smacker_decode_tree(gb, &tmp2, 0, 0);

        skip_bits1(gb);

        res = init_vlc(&vlc[1], SMKTREE_BITS, tmp2.length,

                    tmp2.lengths, sizeof(int), sizeof(int),

                    tmp2.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);

        if(res < 0) {

            av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");

            return -1;

        }

    } else {

        av_log(smk->avctx, AV_LOG_ERROR, "Skipping high bytes tree\n");

    }

    escapes[0]  = get_bits(gb, 8);

    escapes[0] |= get_bits(gb, 8) << 8;

    escapes[1]  = get_bits(gb, 8);

    escapes[1] |= get_bits(gb, 8) << 8;

    escapes[2]  = get_bits(gb, 8);

    escapes[2] |= get_bits(gb, 8) << 8;

    last[0] = last[1] = last[2] = -1;

    ctx.escapes[0] = escapes[0];

    ctx.escapes[1] = escapes[1];

    ctx.escapes[2] = escapes[2];

    ctx.v1 = &vlc[0];

    ctx.v2 = &vlc[1];

    ctx.recode1 = tmp1.values;

    ctx.recode2 = tmp2.values;

    ctx.last = last;

    huff.length = ((size + 3) >> 2) + 3;

    huff.maxlength = 0;

    huff.current = 0;

    huff.values = av_mallocz(huff.length * sizeof(int));

    smacker_decode_bigtree(gb, &huff, &ctx);

    skip_bits1(gb);

    if(ctx.last[0] == -1) ctx.last[0] = huff.current++;

    if(ctx.last[1] == -1) ctx.last[1] = huff.current++;

    if(ctx.last[2] == -1) ctx.last[2] = huff.current++;

    *recodes = huff.values;

    if(vlc[0].table)

        free_vlc(&vlc[0]);

    if(vlc[1].table)

        free_vlc(&vlc[1]);

    av_free(tmp1.bits);

    av_free(tmp1.lengths);

    av_free(tmp1.values);

    av_free(tmp2.bits);

    av_free(tmp2.lengths);

    av_free(tmp2.values);

    return 0;

}

static int decode_header_trees(SmackVContext *smk) {

    GetBitContext gb;

    int mmap_size, mclr_size, full_size, type_size;

    mmap_size = AV_RL32(smk->avctx->extradata);

    mclr_size = AV_RL32(smk->avctx->extradata + 4);

    full_size = AV_RL32(smk->avctx->extradata + 8);

    type_size = AV_RL32(smk->avctx->extradata + 12);

    init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);

    if(!get_bits1(&gb)) {

        av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");

        smk->mmap_tbl = av_malloc(sizeof(int) * 2);

        smk->mmap_tbl[0] = 0;

        smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;

    } else {

        smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size);

    }

    if(!get_bits1(&gb)) {

        av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");

        smk->mclr_tbl = av_malloc(sizeof(int) * 2);

        smk->mclr_tbl[0] = 0;

        smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;

    } else {

        smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size);

    }

    if(!get_bits1(&gb)) {

        av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");

        smk->full_tbl = av_malloc(sizeof(int) * 2);

        smk->full_tbl[0] = 0;

        smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;

    } else {

        smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size);

    }

    if(!get_bits1(&gb)) {

        av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");

        smk->type_tbl = av_malloc(sizeof(int) * 2);

        smk->type_tbl[0] = 0;

        smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;

    } else {

        smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size);

    }

    return 0;

}

static av_always_inline void last_reset(int *recode, int *last) {

    recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;

}

/* get code and update history */

static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {

    register int *table = recode;

    int v, b;

    b = get_bits_count(gb);

    while(*table & SMK_NODE) {

        if(get_bits1(gb))

            table += (*table) & (~SMK_NODE);

        table++;

    }

    v = *table;

    b = get_bits_count(gb) - b;

    if(v != recode[last[0]]) {

        recode[last[2]] = recode[last[1]];

        recode[last[1]] = recode[last[0]];

        recode[last[0]] = v;

    }

    return v;

}

static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    SmackVContext * const smk = avctx->priv_data;

    uint8_t *out;

    uint32_t *pal;

    GetBitContext gb;

    int blocks, blk, bw, bh;

    int i;

    int stride;

    if(buf_size <= 769)

        return 0;

    if(smk->pic.data[0])

            avctx->release_buffer(avctx, &smk->pic);

    smk->pic.reference = 1;

    smk->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;

    if(avctx->reget_buffer(avctx, &smk->pic) < 0){

        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

        return -1;

    }

    /* make the palette available on the way out */

    pal = (uint32_t*)smk->pic.data[1];

    smk->pic.palette_has_changed = buf[0] & 1;

    smk->pic.key_frame = !!(buf[0] & 2);

    if(smk->pic.key_frame)

        smk->pic.pict_type = FF_I_TYPE;

    else

        smk->pic.pict_type = FF_P_TYPE;

    buf++;

    for(i = 0; i < 256; i++)

        *pal++ = bytestream_get_be24(&buf);

    buf_size -= 769;

    last_reset(smk->mmap_tbl, smk->mmap_last);

    last_reset(smk->mclr_tbl, smk->mclr_last);

    last_reset(smk->full_tbl, smk->full_last);

    last_reset(smk->type_tbl, smk->type_last);

    init_get_bits(&gb, buf, buf_size * 8);

    blk = 0;

    bw = avctx->width >> 2;

    bh = avctx->height >> 2;

    blocks = bw * bh;

    out = smk->pic.data[0];

    stride = smk->pic.linesize[0];

    while(blk < blocks) {

        int type, run, mode;

        uint16_t pix;

        type = smk_get_code(&gb, smk->type_tbl, smk->type_last);

        run = block_runs[(type >> 2) & 0x3F];

        switch(type & 3){

        case SMK_BLK_MONO:

            while(run-- && blk < blocks){

                int clr, map;

                int hi, lo;

                clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);

                map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);

                out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;

                hi = clr >> 8;

                lo = clr & 0xFF;

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

                    if(map & 1) out[0] = hi; else out[0] = lo;

                    if(map & 2) out[1] = hi; else out[1] = lo;

                    if(map & 4) out[2] = hi; else out[2] = lo;

                    if(map & 8) out[3] = hi; else out[3] = lo;

                    map >>= 4;

                    out += stride;

                }

                blk++;

            }

            break;

        case SMK_BLK_FULL:

            mode = 0;

            if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes

                if(get_bits1(&gb)) mode = 1;

                else if(get_bits1(&gb)) mode = 2;

            }

            while(run-- && blk < blocks){

                out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;

                switch(mode){

                case 0:

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

                        pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                        AV_WL16(out+2,pix);

                        pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                        AV_WL16(out,pix);

                        out += stride;

                    }

                    break;

                case 1:

                    pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                    out[0] = out[1] = pix & 0xFF;

                    out[2] = out[3] = pix >> 8;

                    out += stride;

                    out[0] = out[1] = pix & 0xFF;

                    out[2] = out[3] = pix >> 8;

                    out += stride;

                    pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                    out[0] = out[1] = pix & 0xFF;

                    out[2] = out[3] = pix >> 8;

                    out += stride;

                    out[0] = out[1] = pix & 0xFF;

                    out[2] = out[3] = pix >> 8;

                    out += stride;

                    break;

                case 2:

                    for(i = 0; i < 2; i++) {

                        uint16_t pix1, pix2;

                        pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                        pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);

                        AV_WL16(out,pix1);

                        AV_WL16(out+2,pix2);

                        out += stride;

                        AV_WL16(out,pix1);

                        AV_WL16(out+2,pix2);

                        out += stride;

                    }

                    break;

                }

                blk++;

            }

            break;

        case SMK_BLK_SKIP:

            while(run-- && blk < blocks)

                blk++;

            break;

        case SMK_BLK_FILL:

            mode = type >> 8;

            while(run-- && blk < blocks){

                uint32_t col;

                out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;

                col = mode * 0x01010101;

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

                    *((uint32_t*)out) = col;

                    out += stride;

                }

                blk++;

            }

            break;

        }

    }

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = smk->pic;

    /* always report that the buffer was completely consumed */

    return buf_size;

}

/*

 *

 * Init smacker decoder

 *

 */

static av_cold int decode_init(AVCodecContext *avctx)

{

    SmackVContext * const c = avctx->priv_data;

    c->avctx = avctx;

    c->pic.data[0] = NULL;

    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {

        return 1;

    }

    avctx->pix_fmt = PIX_FMT_PAL8;

    /* decode huffman trees from extradata */

    if(avctx->extradata_size < 16){

        av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");

        return -1;

    }

    decode_header_trees(c);

    return 0;

}

/*

 *

 * Uninit smacker decoder

 *

 */

static av_cold int decode_end(AVCodecContext *avctx)

{

    SmackVContext * const smk = avctx->priv_data;

    av_freep(&smk->mmap_tbl);

    av_freep(&smk->mclr_tbl);

    av_freep(&smk->full_tbl);

    av_freep(&smk->type_tbl);

    if (smk->pic.data[0])

        avctx->release_buffer(avctx, &smk->pic);

    return 0;

}

static av_cold int smka_decode_init(AVCodecContext *avctx)

{

    avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;

    return 0;

}

/**

 * Decode Smacker audio data

 */

static int smka_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    GetBitContext gb;

    HuffContext h[4];

    VLC vlc[4];

    int16_t *samples = data;

    int8_t *samples8 = data;

    int val;

    int i, res;

    int unp_size;

    int bits, stereo;

    int pred[2] = {0, 0};

    unp_size = AV_RL32(buf);

    init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);

    if(!get_bits1(&gb)){

        av_log(avctx, AV_LOG_INFO, "Sound: no data\n");

        *data_size = 0;

        return 1;

    }

    stereo = get_bits1(&gb);

    bits = get_bits1(&gb);

    if (unp_size & 0xC0000000 || unp_size > *data_size) {

        av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");

        return -1;

    }

    memset(vlc, 0, sizeof(VLC) * 4);

    memset(h, 0, sizeof(HuffContext) * 4);

    // Initialize

    for(i = 0; i < (1 << (bits + stereo)); i++) {

        h[i].length = 256;

        h[i].maxlength = 0;

        h[i].current = 0;

        h[i].bits = av_mallocz(256 * 4);

        h[i].lengths = av_mallocz(256 * sizeof(int));

        h[i].values = av_mallocz(256 * sizeof(int));

        skip_bits1(&gb);

        smacker_decode_tree(&gb, &h[i], 0, 0);

        skip_bits1(&gb);

        if(h[i].current > 1) {

            res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,

                    h[i].lengths, sizeof(int), sizeof(int),

                    h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);

            if(res < 0) {

                av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");

                return -1;

            }

        }

    }

    if(bits) { //decode 16-bit data

        for(i = stereo; i >= 0; i--)

            pred[i] = bswap_16(get_bits(&gb, 16));

        for(i = 0; i < stereo; i++)

            *samples++ = pred[i];

        for(i = 0; i < unp_size / 2; i++) {

            if(i & stereo) {

                if(vlc[2].table)

                    res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                val  = h[2].values[res];

                if(vlc[3].table)

                    res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                val |= h[3].values[res] << 8;

                pred[1] += (int16_t)val;

                *samples++ = pred[1];

            } else {

                if(vlc[0].table)

                    res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                val  = h[0].values[res];

                if(vlc[1].table)

                    res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                val |= h[1].values[res] << 8;

                pred[0] += val;

                *samples++ = pred[0];

            }

        }

    } else { //8-bit data

        for(i = stereo; i >= 0; i--)

            pred[i] = get_bits(&gb, 8);

        for(i = 0; i < stereo; i++)

            *samples8++ = pred[i];

        for(i = 0; i < unp_size; i++) {

            if(i & stereo){

                if(vlc[1].table)

                    res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                pred[1] += (int8_t)h[1].values[res];

                *samples8++ = pred[1];

            } else {

                if(vlc[0].table)

                    res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);

                else

                    res = 0;

                pred[0] += (int8_t)h[0].values[res];

                *samples8++ = pred[0];

            }

        }

    }

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

        if(vlc[i].table)

            free_vlc(&vlc[i]);

        if(h[i].bits)

            av_free(h[i].bits);

        if(h[i].lengths)

            av_free(h[i].lengths);

        if(h[i].values)

            av_free(h[i].values);

    }

    *data_size = unp_size;

    return buf_size;

}

AVCodec smacker_decoder = {

    "smackvid",

    CODEC_TYPE_VIDEO,

    CODEC_ID_SMACKVIDEO,

    sizeof(SmackVContext),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    .long_name = NULL_IF_CONFIG_SMALL("Smacker video"),

};

AVCodec smackaud_decoder = {

    "smackaud",

    CODEC_TYPE_AUDIO,

    CODEC_ID_SMACKAUDIO,

    0,

    smka_decode_init,

    NULL,

    NULL,

    smka_decode_frame,

    .long_name = NULL_IF_CONFIG_SMALL("Smacker audio"),

};