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ffmpeg / libavcodec / eacmv.c @ 2912e87a

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/*
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 * Electronic Arts CMV Video Decoder
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 * Copyright (c) 2007-2008 Peter Ross
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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 */
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/**
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 * @file
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 * Electronic Arts CMV Video Decoder
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 * by Peter Ross (pross@xvid.org)
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 *
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 * Technical details here:
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 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
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 */
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#include "libavutil/intreadwrite.h"
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#include "libavutil/imgutils.h"
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#include "avcodec.h"
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typedef struct CmvContext {
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    AVCodecContext *avctx;
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    AVFrame frame;        ///< current
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    AVFrame last_frame;   ///< last
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    AVFrame last2_frame;  ///< second-last
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    int width, height;
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    unsigned int palette[AVPALETTE_COUNT];
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} CmvContext;
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static av_cold int cmv_decode_init(AVCodecContext *avctx){
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    CmvContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    return 0;
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}
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static void cmv_decode_intra(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
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    unsigned char *dst = s->frame.data[0];
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    int i;
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    for (i=0; i < s->avctx->height && buf+s->avctx->width<=buf_end; i++) {
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        memcpy(dst, buf, s->avctx->width);
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        dst += s->frame.linesize[0];
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        buf += s->avctx->width;
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    }
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}
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static void cmv_motcomp(unsigned char *dst, int dst_stride,
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                        const unsigned char *src, int src_stride,
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                        int x, int y,
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                        int xoffset, int yoffset,
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                        int width, int height){
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    int i,j;
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    for(j=y;j<y+4;j++)
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    for(i=x;i<x+4;i++)
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    {
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        if (i+xoffset>=0 && i+xoffset<width &&
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            j+yoffset>=0 && j+yoffset<height) {
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            dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
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        }else{
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            dst[j*dst_stride + i] = 0;
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        }
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    }
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}
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static void cmv_decode_inter(CmvContext * s, const uint8_t *buf, const uint8_t *buf_end){
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    const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
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    int x,y,i;
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    i = 0;
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    for(y=0; y<s->avctx->height/4; y++)
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    for(x=0; x<s->avctx->width/4 && buf+i<buf_end; x++) {
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        if (buf[i]==0xFF) {
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            unsigned char *dst = s->frame.data[0] + (y*4)*s->frame.linesize[0] + x*4;
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            if (raw+16<buf_end && *raw==0xFF) { /* intra */
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                raw++;
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                memcpy(dst, raw, 4);
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                memcpy(dst+s->frame.linesize[0], raw+4, 4);
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                memcpy(dst+2*s->frame.linesize[0], raw+8, 4);
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                memcpy(dst+3*s->frame.linesize[0], raw+12, 4);
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                raw+=16;
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            }else if(raw<buf_end) {  /* inter using second-last frame as reference */
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                int xoffset = (*raw & 0xF) - 7;
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                int yoffset = ((*raw >> 4)) - 7;
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                if (s->last2_frame.data[0])
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                    cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
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                                s->last2_frame.data[0], s->last2_frame.linesize[0],
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                                x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
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                raw++;
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            }
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        }else{  /* inter using last frame as reference */
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            int xoffset = (buf[i] & 0xF) - 7;
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            int yoffset = ((buf[i] >> 4)) - 7;
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            cmv_motcomp(s->frame.data[0], s->frame.linesize[0],
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                      s->last_frame.data[0], s->last_frame.linesize[0],
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                      x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
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        }
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        i++;
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    }
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}
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static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
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{
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    int pal_start, pal_count, i;
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    if(buf+16>=buf_end) {
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        av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
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        return;
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    }
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    s->width  = AV_RL16(&buf[4]);
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    s->height = AV_RL16(&buf[6]);
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    if (s->avctx->width!=s->width || s->avctx->height!=s->height)
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        avcodec_set_dimensions(s->avctx, s->width, s->height);
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    s->avctx->time_base.num = 1;
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    s->avctx->time_base.den = AV_RL16(&buf[10]);
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    pal_start = AV_RL16(&buf[12]);
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    pal_count = AV_RL16(&buf[14]);
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    buf += 16;
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    for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
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        s->palette[i] = AV_RB24(buf);
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        buf += 3;
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    }
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}
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#define EA_PREAMBLE_SIZE 8
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#define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
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static int cmv_decode_frame(AVCodecContext *avctx,
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                            void *data, int *data_size,
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                            AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    CmvContext *s = avctx->priv_data;
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    const uint8_t *buf_end = buf + buf_size;
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    if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
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        cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
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        return buf_size;
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    }
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    if (av_image_check_size(s->width, s->height, 0, s->avctx))
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        return -1;
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    /* shuffle */
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    if (s->last2_frame.data[0])
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        avctx->release_buffer(avctx, &s->last2_frame);
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    FFSWAP(AVFrame, s->last_frame, s->last2_frame);
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    FFSWAP(AVFrame, s->frame, s->last_frame);
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    s->frame.reference = 1;
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    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
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    if (avctx->get_buffer(avctx, &s->frame)<0) {
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        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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        return -1;
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    }
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    memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
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    buf += EA_PREAMBLE_SIZE;
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    if ((buf[0]&1)) {  // subtype
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        cmv_decode_inter(s, buf+2, buf_end);
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        s->frame.key_frame = 0;
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        s->frame.pict_type = FF_P_TYPE;
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    }else{
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        s->frame.key_frame = 1;
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        s->frame.pict_type = FF_I_TYPE;
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        cmv_decode_intra(s, buf+2, buf_end);
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = s->frame;
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    return buf_size;
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}
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static av_cold int cmv_decode_end(AVCodecContext *avctx){
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    CmvContext *s = avctx->priv_data;
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    if (s->frame.data[0])
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        s->avctx->release_buffer(avctx, &s->frame);
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    if (s->last_frame.data[0])
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        s->avctx->release_buffer(avctx, &s->last_frame);
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    if (s->last2_frame.data[0])
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        s->avctx->release_buffer(avctx, &s->last2_frame);
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    return 0;
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}
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AVCodec ff_eacmv_decoder = {
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    "eacmv",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_CMV,
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    sizeof(CmvContext),
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    cmv_decode_init,
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    NULL,
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    cmv_decode_end,
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    cmv_decode_frame,
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    CODEC_CAP_DR1,
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    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
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};