PeerStreamer

/*

 * Chronomaster DFA Video Decoder

 * Copyright (c) 2011 Konstantin Shishkov

 * based on work by Vladimir "VAG" Gneushev

 *

 * 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

 */

#include "avcodec.h"

#include "libavutil/intreadwrite.h"

#include "bytestream.h"

#include "libavutil/lzo.h" // for av_memcpy_backptr

typedef struct DfaContext {

    AVFrame pic;

    uint32_t pal[256];

    uint8_t *frame_buf;

} DfaContext;

static av_cold int dfa_decode_init(AVCodecContext *avctx)

{

    DfaContext *s = avctx->priv_data;

    avctx->pix_fmt = PIX_FMT_PAL8;

    s->frame_buf = av_mallocz(avctx->width * avctx->height + AV_LZO_OUTPUT_PADDING);

    if (!s->frame_buf)

        return AVERROR(ENOMEM);

    return 0;

}

static int decode_copy(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const int size = width * height;

    if (src_end - src < size)

        return -1;

    bytestream_get_buffer(&src, frame, size);

    return 0;

}

static int decode_tsw1(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const uint8_t *frame_start = frame;

    const uint8_t *frame_end   = frame + width * height;

    int mask = 0x10000, bitbuf = 0;

    int v, count, segments;

    unsigned offset;

    segments = bytestream_get_le32(&src);

    offset   = bytestream_get_le32(&src);

    if (frame_end - frame <= offset)

        return -1;

    frame += offset;

    while (segments--) {

        if (mask == 0x10000) {

            if (src >= src_end)

                return -1;

            bitbuf = bytestream_get_le16(&src);

            mask = 1;

        }

        if (src_end - src < 2 || frame_end - frame < 2)

            return -1;

        if (bitbuf & mask) {

            v = bytestream_get_le16(&src);

            offset = (v & 0x1FFF) << 1;

            count = ((v >> 13) + 2) << 1;

            if (frame - frame_start < offset || frame_end - frame < count)

                return -1;

            av_memcpy_backptr(frame, offset, count);

            frame += count;

        } else {

            *frame++ = *src++;

            *frame++ = *src++;

        }

        mask <<= 1;

    }

    return 0;

}

static int decode_dsw1(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const uint8_t *frame_start = frame;

    const uint8_t *frame_end   = frame + width * height;

    int mask = 0x10000, bitbuf = 0;

    int v, offset, count, segments;

    segments = bytestream_get_le16(&src);

    while (segments--) {

        if (mask == 0x10000) {

            if (src >= src_end)

                return -1;

            bitbuf = bytestream_get_le16(&src);

            mask = 1;

        }

        if (src_end - src < 2 || frame_end - frame < 2)

            return -1;

        if (bitbuf & mask) {

            v = bytestream_get_le16(&src);

            offset = (v & 0x1FFF) << 1;

            count = ((v >> 13) + 2) << 1;

            if (frame - frame_start < offset || frame_end - frame < count)

                return -1;

            // can't use av_memcpy_backptr() since it can overwrite following pixels

            for (v = 0; v < count; v++)

                frame[v] = frame[v - offset];

            frame += count;

        } else if (bitbuf & (mask << 1)) {

            frame += bytestream_get_le16(&src);

        } else {

            *frame++ = *src++;

            *frame++ = *src++;

        }

        mask <<= 2;

    }

    return 0;

}

static int decode_dds1(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const uint8_t *frame_start = frame;

    const uint8_t *frame_end   = frame + width * height;

    int mask = 0x10000, bitbuf = 0;

    int i, v, offset, count, segments;

    segments = bytestream_get_le16(&src);

    while (segments--) {

        if (mask == 0x10000) {

            if (src >= src_end)

                return -1;

            bitbuf = bytestream_get_le16(&src);

            mask = 1;

        }

        if (src_end - src < 2 || frame_end - frame < 2)

            return -1;

        if (bitbuf & mask) {

            v = bytestream_get_le16(&src);

            offset = (v & 0x1FFF) << 2;

            count = ((v >> 13) + 2) << 1;

            if (frame - frame_start < offset || frame_end - frame < count*2 + width)

                return -1;

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

                frame[0] = frame[1] =

                frame[width] = frame[width + 1] = frame[-offset];

                frame += 2;

            }

        } else if (bitbuf & (mask << 1)) {

            frame += bytestream_get_le16(&src) * 2;

        } else {

            frame[0] = frame[1] =

            frame[width] = frame[width + 1] =  *src++;

            frame += 2;

            frame[0] = frame[1] =

            frame[width] = frame[width + 1] =  *src++;

            frame += 2;

        }

        mask <<= 2;

    }

    return 0;

}

static int decode_bdlt(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const uint8_t *frame_end = frame + width * height;

    uint8_t *line_ptr;

    int count, lines, segments;

    count = bytestream_get_le16(&src);

    if (count >= height)

        return -1;

    frame += width * count;

    lines = bytestream_get_le16(&src);

    if (count + lines > height || src >= src_end)

        return -1;

    while (lines--) {

        line_ptr = frame;

        frame += width;

        segments = *src++;

        while (segments--) {

            if (src_end - src < 3)

                return -1;

            if (frame - line_ptr <= *src)

                return -1;

            line_ptr += *src++;

            count = (int8_t)*src++;

            if (count >= 0) {

                if (frame - line_ptr < count || src_end - src < count)

                    return -1;

                bytestream_get_buffer(&src, line_ptr, count);

            } else {

                count = -count;

                if (frame - line_ptr < count || src >= src_end)

                    return -1;

                memset(line_ptr, *src++, count);

            }

            line_ptr += count;

        }

    }

    return 0;

}

static int decode_wdlt(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    const uint8_t *frame_end   = frame + width * height;

    uint8_t *line_ptr;

    int count, i, v, lines, segments;

    lines = bytestream_get_le16(&src);

    if (lines > height || src >= src_end)

        return -1;

    while (lines--) {

        segments = bytestream_get_le16(&src);

        while ((segments & 0xC000) == 0xC000) {

            unsigned delta = -((int16_t)segments * width);

            if (frame_end - frame <= delta)

                return -1;

            frame    += delta;

            segments = bytestream_get_le16(&src);

        }

        if (segments & 0x8000) {

            frame[width - 1] = segments & 0xFF;

            segments = bytestream_get_le16(&src);

        }

        line_ptr = frame;

        frame += width;

        while (segments--) {

            if (src_end - src < 2)

                return -1;

            if (frame - line_ptr <= *src)

                return -1;

            line_ptr += *src++;

            count = (int8_t)*src++;

            if (count >= 0) {

                if (frame - line_ptr < count*2 || src_end - src < count*2)

                    return -1;

                bytestream_get_buffer(&src, line_ptr, count*2);

                line_ptr += count * 2;

            } else {

                count = -count;

                if (frame - line_ptr < count*2 || src_end - src < 2)

                    return -1;

                v = bytestream_get_le16(&src);

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

                    bytestream_put_le16(&line_ptr, v);

            }

        }

    }

    return 0;

}

static int decode_unk6(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    return -1;

}

static int decode_blck(uint8_t *frame, int width, int height,

                       const uint8_t *src, const uint8_t *src_end)

{

    memset(frame, 0, width * height);

    return 0;

}

typedef int (*chunk_decoder)(uint8_t *frame, int width, int height,

                             const uint8_t *src, const uint8_t *src_end);

static const chunk_decoder decoder[8] = {

    decode_copy, decode_tsw1, decode_bdlt, decode_wdlt,

    decode_unk6, decode_dsw1, decode_blck, decode_dds1,

};

static const char* chunk_name[8] = {

    "COPY", "TSW1", "BDLT", "WDLT", "????", "DSW1", "BLCK", "DDS1"

};

static int dfa_decode_frame(AVCodecContext *avctx,

                            void *data, int *data_size,

                            AVPacket *avpkt)

{

    DfaContext *s = avctx->priv_data;

    const uint8_t *buf = avpkt->data;

    const uint8_t *buf_end = avpkt->data + avpkt->size;

    const uint8_t *tmp_buf;

    uint32_t chunk_type, chunk_size;

    uint8_t *dst;

    int ret;

    int i, pal_elems;

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

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

    if ((ret = avctx->get_buffer(avctx, &s->pic))) {

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

        return ret;

    }

    while (buf < buf_end) {

        chunk_size = AV_RL32(buf + 4);

        chunk_type = AV_RL32(buf + 8);

        buf += 12;

        if (buf_end - buf < chunk_size) {

            av_log(avctx, AV_LOG_ERROR, "Chunk size is too big (%d bytes)\n", chunk_size);

            return -1;

        }

        if (!chunk_type)

            break;

        if (chunk_type == 1) {

            pal_elems = FFMIN(chunk_size / 3, 256);

            tmp_buf = buf;

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

                s->pal[i] = bytestream_get_be24(&tmp_buf) << 2;

                s->pal[i] |= (s->pal[i] >> 6) & 0x333;

            }

            s->pic.palette_has_changed = 1;

        } else if (chunk_type <= 9) {

            if (decoder[chunk_type - 2](s->frame_buf, avctx->width, avctx->height,

                                        buf, buf + chunk_size)) {

                av_log(avctx, AV_LOG_ERROR, "Error decoding %s chunk\n",

                       chunk_name[chunk_type - 2]);

                return -1;

            }

        } else {

            av_log(avctx, AV_LOG_WARNING, "Ignoring unknown chunk type %d\n",

                   chunk_type);

        }

        buf += chunk_size;

    }

    buf = s->frame_buf;

    dst = s->pic.data[0];

    for (i = 0; i < avctx->height; i++) {

        memcpy(dst, buf, avctx->width);

        dst += s->pic.linesize[0];

        buf += avctx->width;

    }

    memcpy(s->pic.data[1], s->pal, sizeof(s->pal));

    *data_size = sizeof(AVFrame);

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

    return avpkt->size;

}

static av_cold int dfa_decode_end(AVCodecContext *avctx)

{

    DfaContext *s = avctx->priv_data;

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

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

    av_freep(&s->frame_buf);

    return 0;

}

AVCodec ff_dfa_decoder = {

    "dfa",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_DFA,

    sizeof(DfaContext),

    dfa_decode_init,

    NULL,

    dfa_decode_end,

    dfa_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Chronomaster DFA"),

};