PeerStreamer

/*

 * DPX (.dpx) image decoder

 * Copyright (c) 2009 Jimmy Christensen

 *

 * 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 "libavutil/intreadwrite.h"

#include "libavutil/imgutils.h"

#include "bytestream.h"

#include "avcodec.h"

typedef struct DPXContext {

    AVFrame picture;

} DPXContext;

static unsigned int read32(const uint8_t **ptr, int is_big)

{

    unsigned int temp;

    if (is_big) {

        temp = AV_RB32(*ptr);

    } else {

        temp = AV_RL32(*ptr);

    }

    *ptr += 4;

    return temp;

}

static inline unsigned make_16bit(unsigned value)

{

    // mask away invalid bits

    value &= 0xFFC0;

    // correctly expand to 16 bits

    return value + (value >> 10);

}

static int decode_frame(AVCodecContext *avctx,

                        void *data,

                        int *data_size,

                        AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

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

    int buf_size       = avpkt->size;

    DPXContext *const s = avctx->priv_data;

    AVFrame *picture  = data;

    AVFrame *const p = &s->picture;

    uint8_t *ptr;

    int magic_num, offset, endian;

    int x, y;

    int w, h, stride, bits_per_color, descriptor, elements, target_packet_size, source_packet_size;

    unsigned int rgbBuffer;

    if (avpkt->size <= 1634) {

        av_log(avctx, AV_LOG_ERROR, "Packet too small for DPX header\n");

        return AVERROR_INVALIDDATA;

    }

    magic_num = AV_RB32(buf);

    buf += 4;

    /* Check if the files "magic number" is "SDPX" which means it uses

     * big-endian or XPDS which is for little-endian files */

    if (magic_num == AV_RL32("SDPX")) {

        endian = 0;

    } else if (magic_num == AV_RB32("SDPX")) {

        endian = 1;

    } else {

        av_log(avctx, AV_LOG_ERROR, "DPX marker not found\n");

        return -1;

    }

    offset = read32(&buf, endian);

    if (avpkt->size <= offset) {

        av_log(avctx, AV_LOG_ERROR, "Invalid data start offset\n");

        return AVERROR_INVALIDDATA;

    }

    // Need to end in 0x304 offset from start of file

    buf = avpkt->data + 0x304;

    w = read32(&buf, endian);

    h = read32(&buf, endian);

    // Need to end in 0x320 to read the descriptor

    buf += 20;

    descriptor = buf[0];

    // Need to end in 0x323 to read the bits per color

    buf += 3;

    avctx->bits_per_raw_sample =

    bits_per_color = buf[0];

    buf += 825;

    avctx->sample_aspect_ratio.num = read32(&buf, endian);

    avctx->sample_aspect_ratio.den = read32(&buf, endian);

    switch (descriptor) {

        case 51: // RGBA

            elements = 4;

            break;

        case 50: // RGB

            elements = 3;

            break;

        default:

            av_log(avctx, AV_LOG_ERROR, "Unsupported descriptor %d\n", descriptor);

            return -1;

    }

    switch (bits_per_color) {

        case 8:

            if (elements == 4) {

                avctx->pix_fmt = PIX_FMT_RGBA;

            } else {

                avctx->pix_fmt = PIX_FMT_RGB24;

            }

            source_packet_size = elements;

            target_packet_size = elements;

            break;

        case 10:

            avctx->pix_fmt = PIX_FMT_RGB48;

            target_packet_size = 6;

            source_packet_size = 4;

            break;

        case 12:

        case 16:

            if (endian) {

                avctx->pix_fmt = PIX_FMT_RGB48BE;

            } else {

                avctx->pix_fmt = PIX_FMT_RGB48LE;

            }

            target_packet_size = 6;

            source_packet_size = elements * 2;

            break;

        default:

            av_log(avctx, AV_LOG_ERROR, "Unsupported color depth : %d\n", bits_per_color);

            return -1;

    }

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

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

    if (av_image_check_size(w, h, 0, avctx))

        return -1;

    if (w != avctx->width || h != avctx->height)

        avcodec_set_dimensions(avctx, w, h);

    if (avctx->get_buffer(avctx, p) < 0) {

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

        return -1;

    }

    // Move pointer to offset from start of file

    buf =  avpkt->data + offset;

    ptr    = p->data[0];

    stride = p->linesize[0];

    if (source_packet_size*avctx->width*avctx->height > buf_end - buf) {

        av_log(avctx, AV_LOG_ERROR, "Overread buffer. Invalid header?\n");

        return -1;

    }

    switch (bits_per_color) {

        case 10:

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

               uint16_t *dst = (uint16_t*)ptr;

               for (y = 0; y < avctx->width; y++) {

                   rgbBuffer = read32(&buf, endian);

                   // Read out the 10-bit colors and convert to 16-bit

                   *dst++ = make_16bit(rgbBuffer >> 16);

                   *dst++ = make_16bit(rgbBuffer >>  6);

                   *dst++ = make_16bit(rgbBuffer <<  4);

               }

               ptr += stride;

            }

            break;

        case 8:

        case 12: // Treat 12-bit as 16-bit

        case 16:

            if (source_packet_size == target_packet_size) {

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

                    memcpy(ptr, buf, target_packet_size*avctx->width);

                    ptr += stride;

                    buf += source_packet_size*avctx->width;

                }

            } else {

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

                    uint8_t *dst = ptr;

                    for (y = 0; y < avctx->width; y++) {

                        memcpy(dst, buf, target_packet_size);

                        dst += target_packet_size;

                        buf += source_packet_size;

                    }

                    ptr += stride;

                }

            }

            break;

    }

    *picture   = s->picture;

    *data_size = sizeof(AVPicture);

    return buf_size;

}

static av_cold int decode_init(AVCodecContext *avctx)

{

    DPXContext *s = avctx->priv_data;

    avcodec_get_frame_defaults(&s->picture);

    avctx->coded_frame = &s->picture;

    return 0;

}

static av_cold int decode_end(AVCodecContext *avctx)

{

    DPXContext *s = avctx->priv_data;

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

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

    return 0;

}

AVCodec ff_dpx_decoder = {

    "dpx",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_DPX,

    sizeof(DPXContext),

    decode_init,

    NULL,

    decode_end,

    decode_frame,

    0,

    NULL,

    .long_name = NULL_IF_CONFIG_SMALL("DPX image"),

};