PeerStreamer

/*

 * MxPEG decoder

 * Copyright (c) 2011 Anatoly Nenashev

 *

 * This file is part of Libav.

 *

 * Libav 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.

 *

 * Libav 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 Libav; if not, write to the Free Software

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

 */

/**

 * @file

 * MxPEG decoder

 */

#include "mjpeg.h"

#include "mjpegdec.h"

typedef struct MXpegDecodeContext {

    MJpegDecodeContext jpg;

    AVFrame picture[2]; /* pictures array */

    int picture_index; /* index of current picture */

    int got_sof_data; /* true if SOF data successfully parsed */

    int got_mxm_bitmask; /* true if MXM bitmask available */

    uint8_t *mxm_bitmask; /* bitmask buffer */

    unsigned bitmask_size; /* size of bitmask */

    int has_complete_frame; /* true if has complete frame */

    uint8_t *completion_bitmask; /* completion bitmask of macroblocks */

    unsigned mb_width, mb_height; /* size of picture in MB's from MXM header */

} MXpegDecodeContext;

static av_cold int mxpeg_decode_init(AVCodecContext *avctx)

{

    MXpegDecodeContext *s = avctx->priv_data;

    s->picture[0].reference = s->picture[1].reference = 3;

    s->jpg.picture_ptr      = &s->picture[0];

    ff_mjpeg_decode_init(avctx);

    return 0;

}

static int mxpeg_decode_app(MXpegDecodeContext *s,

                            const uint8_t *buf_ptr, int buf_size)

{

    int len;

    if (buf_size < 2)

        return 0;

    len = AV_RB16(buf_ptr);

    skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));

    return 0;

}

static int mxpeg_decode_mxm(MXpegDecodeContext *s,

                            const uint8_t *buf_ptr, int buf_size)

{

    unsigned bitmask_size, mb_count;

    int i;

    s->mb_width  = AV_RL16(buf_ptr+4);

    s->mb_height = AV_RL16(buf_ptr+6);

    mb_count = s->mb_width * s->mb_height;

    bitmask_size = (mb_count + 7) >> 3;

    if (bitmask_size > buf_size - 12) {

        av_log(s->jpg.avctx, AV_LOG_ERROR,

               "MXM bitmask is not complete\n");

        return AVERROR(EINVAL);

    }

    if (s->bitmask_size != bitmask_size) {

        av_freep(&s->mxm_bitmask);

        s->mxm_bitmask = av_malloc(bitmask_size);

        if (!s->mxm_bitmask) {

            av_log(s->jpg.avctx, AV_LOG_ERROR,

                   "MXM bitmask memory allocation error\n");

            return AVERROR(ENOMEM);

        }

        av_freep(&s->completion_bitmask);

        s->completion_bitmask = av_mallocz(bitmask_size);

        if (!s->completion_bitmask) {

            av_log(s->jpg.avctx, AV_LOG_ERROR,

                   "Completion bitmask memory allocation error\n");

            return AVERROR(ENOMEM);

        }

        s->bitmask_size = bitmask_size;

    }

    memcpy(s->mxm_bitmask, buf_ptr + 12, bitmask_size);

    s->got_mxm_bitmask = 1;

    if (!s->has_complete_frame) {

        uint8_t completion_check = 0xFF;

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

            s->completion_bitmask[i] |= s->mxm_bitmask[i];

            completion_check &= s->completion_bitmask[i];

        }

        s->has_complete_frame = !(completion_check ^ 0xFF);

    }

    return 0;

}

static int mxpeg_decode_com(MXpegDecodeContext *s,

                            const uint8_t *buf_ptr, int buf_size)

{

    int len, ret = 0;

    if (buf_size < 2)

        return 0;

    len = AV_RB16(buf_ptr);

    if (len > 14 && len <= buf_size && !strncmp(buf_ptr + 2, "MXM", 3)) {

        ret = mxpeg_decode_mxm(s, buf_ptr + 2, len - 2);

    }

    skip_bits(&s->jpg.gb, 8*FFMIN(len,buf_size));

    return ret;

}

static int mxpeg_check_dimensions(MXpegDecodeContext *s, MJpegDecodeContext *jpg,

                                  AVFrame *reference_ptr)

{

    if ((jpg->width + 0x0F)>>4 != s->mb_width ||

        (jpg->height + 0x0F)>>4 != s->mb_height) {

        av_log(jpg->avctx, AV_LOG_ERROR,

               "Picture dimensions stored in SOF and MXM mismatch\n");

        return AVERROR(EINVAL);

    }

    if (reference_ptr->data[0]) {

        int i;

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

            if ( (!reference_ptr->data[i] ^ !jpg->picture_ptr->data[i]) ||

                 reference_ptr->linesize[i] != jpg->picture_ptr->linesize[i]) {

                av_log(jpg->avctx, AV_LOG_ERROR,

                       "Dimensions of current and reference picture mismatch\n");

                return AVERROR(EINVAL);

            }

        }

    }

    return 0;

}

static int mxpeg_decode_frame(AVCodecContext *avctx,

                          void *data, int *data_size,

                          AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    MXpegDecodeContext *s = avctx->priv_data;

    MJpegDecodeContext *jpg = &s->jpg;

    const uint8_t *buf_end, *buf_ptr;

    const uint8_t *unescaped_buf_ptr;

    int unescaped_buf_size;

    int start_code;

    AVFrame *picture = data;

    int ret;

    buf_ptr = buf;

    buf_end = buf + buf_size;

    jpg->got_picture = 0;

    s->got_mxm_bitmask = 0;

    while (buf_ptr < buf_end) {

        start_code = ff_mjpeg_find_marker(jpg, &buf_ptr, buf_end,

                                          &unescaped_buf_ptr, &unescaped_buf_size);

        if (start_code < 0)

            goto the_end;

        {

            init_get_bits(&jpg->gb, unescaped_buf_ptr, unescaped_buf_size*8);

            if (start_code >= APP0 && start_code <= APP15) {

                mxpeg_decode_app(s, unescaped_buf_ptr, unescaped_buf_size);

            }

            switch (start_code) {

            case SOI:

                if (jpg->got_picture) //emulating EOI

                    goto the_end;

                break;

            case EOI:

                goto the_end;

            case DQT:

                ret = ff_mjpeg_decode_dqt(jpg);

                if (ret < 0) {

                    av_log(avctx, AV_LOG_ERROR,

                           "quantization table decode error\n");

                    return ret;

                }

                break;

            case DHT:

                ret = ff_mjpeg_decode_dht(jpg);

                if (ret < 0) {

                    av_log(avctx, AV_LOG_ERROR,

                           "huffman table decode error\n");

                    return ret;

                }

                break;

            case COM:

                ret = mxpeg_decode_com(s, unescaped_buf_ptr,

                                       unescaped_buf_size);

                if (ret < 0)

                    return ret;

                break;

            case SOF0:

                s->got_sof_data = 0;

                ret = ff_mjpeg_decode_sof(jpg);

                if (ret < 0) {

                    av_log(avctx, AV_LOG_ERROR,

                           "SOF data decode error\n");

                    return ret;

                }

                if (jpg->interlaced) {

                    av_log(avctx, AV_LOG_ERROR,

                           "Interlaced mode not supported in MxPEG\n");

                    return AVERROR(EINVAL);

                }

                s->got_sof_data = 1;

                break;

            case SOS:

                if (!s->got_sof_data) {

                    av_log(avctx, AV_LOG_WARNING,

                           "Can not process SOS without SOF data, skipping\n");

                    break;

                }

                if (!jpg->got_picture) {

                    if (jpg->first_picture) {

                        av_log(avctx, AV_LOG_WARNING,

                               "First picture has no SOF, skipping\n");

                        break;

                    }

                    if (!s->got_mxm_bitmask){

                        av_log(avctx, AV_LOG_WARNING,

                               "Non-key frame has no MXM, skipping\n");

                        break;

                    }

                    /* use stored SOF data to allocate current picture */

                    if (jpg->picture_ptr->data[0])

                        avctx->release_buffer(avctx, jpg->picture_ptr);

                    if (avctx->get_buffer(avctx, jpg->picture_ptr) < 0) {

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

                        return AVERROR(ENOMEM);

                    }

                    jpg->picture_ptr->pict_type = FF_P_TYPE;

                    jpg->picture_ptr->key_frame = 0;

                    jpg->got_picture = 1;

                } else {

                    jpg->picture_ptr->pict_type = FF_I_TYPE;

                    jpg->picture_ptr->key_frame = 1;

                }

                if (s->got_mxm_bitmask) {

                    AVFrame *reference_ptr = &s->picture[s->picture_index ^ 1];

                    if (mxpeg_check_dimensions(s, jpg, reference_ptr) < 0)

                        break;

                    /* allocate dummy reference picture if needed */

                    if (!reference_ptr->data[0] &&

                        avctx->get_buffer(avctx, reference_ptr) < 0) {

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

                        return AVERROR(ENOMEM);

                    }

                    ff_mjpeg_decode_sos(jpg, s->mxm_bitmask, reference_ptr);

                } else {

                    ff_mjpeg_decode_sos(jpg, NULL, NULL);

                }

                break;

            }

            buf_ptr += (get_bits_count(&jpg->gb)+7) >> 3;

        }

    }

the_end:

    if (jpg->got_picture) {

        *data_size = sizeof(AVFrame);

        *picture = *jpg->picture_ptr;

        s->picture_index ^= 1;

        jpg->picture_ptr = &s->picture[s->picture_index];

        if (!s->has_complete_frame) {

            if (!s->got_mxm_bitmask)

                s->has_complete_frame = 1;

            else

                *data_size = 0;

        }

    }

    return buf_ptr - buf;

}

static av_cold int mxpeg_decode_end(AVCodecContext *avctx)

{

    MXpegDecodeContext *s = avctx->priv_data;

    MJpegDecodeContext *jpg = &s->jpg;

    int i;

    jpg->picture_ptr = NULL;

    ff_mjpeg_decode_end(avctx);

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

        if (s->picture[i].data[0])

            avctx->release_buffer(avctx, &s->picture[i]);

    }

    av_freep(&s->mxm_bitmask);

    av_freep(&s->completion_bitmask);

    return 0;

}

AVCodec ff_mxpeg_decoder = {

    .name           = "mxpeg",

    .long_name      = NULL_IF_CONFIG_SMALL("Mobotix MxPEG video"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = CODEC_ID_MXPEG,

    .priv_data_size = sizeof(MXpegDecodeContext),

    .init           = mxpeg_decode_init,

    .close          = mxpeg_decode_end,

    .decode         = mxpeg_decode_frame,

    .capabilities   = CODEC_CAP_DR1,

    .max_lowres     = 3

};