yading@10: /*
yading@10:  * Electronic Arts CMV Video Decoder
yading@10:  * Copyright (c) 2007-2008 Peter Ross
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Electronic Arts CMV Video Decoder
yading@10:  * by Peter Ross (pross@xvid.org)
yading@10:  *
yading@10:  * Technical details here:
yading@10:  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_CMV
yading@10:  */
yading@10: 
yading@10: #include "libavutil/common.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "libavutil/imgutils.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: typedef struct CmvContext {
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame *last_frame;   ///< last
yading@10:     AVFrame *last2_frame;  ///< second-last
yading@10:     int width, height;
yading@10:     unsigned int palette[AVPALETTE_COUNT];
yading@10: } CmvContext;
yading@10: 
yading@10: static av_cold int cmv_decode_init(AVCodecContext *avctx){
yading@10:     CmvContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     s->last_frame  = av_frame_alloc();
yading@10:     s->last2_frame = av_frame_alloc();
yading@10:     if (!s->last_frame || !s->last2_frame) {
yading@10:         av_frame_free(&s->last_frame);
yading@10:         av_frame_free(&s->last2_frame);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static void cmv_decode_intra(CmvContext * s, AVFrame *frame,
yading@10:                              const uint8_t *buf, const uint8_t *buf_end)
yading@10: {
yading@10:     unsigned char *dst = frame->data[0];
yading@10:     int i;
yading@10: 
yading@10:     for (i=0; i < s->avctx->height && buf_end - buf >= s->avctx->width; i++) {
yading@10:         memcpy(dst, buf, s->avctx->width);
yading@10:         dst += frame->linesize[0];
yading@10:         buf += s->avctx->width;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void cmv_motcomp(unsigned char *dst, int dst_stride,
yading@10:                         const unsigned char *src, int src_stride,
yading@10:                         int x, int y,
yading@10:                         int xoffset, int yoffset,
yading@10:                         int width, int height){
yading@10:     int i,j;
yading@10: 
yading@10:     for(j=y;j<y+4;j++)
yading@10:     for(i=x;i<x+4;i++)
yading@10:     {
yading@10:         if (i+xoffset>=0 && i+xoffset<width &&
yading@10:             j+yoffset>=0 && j+yoffset<height) {
yading@10:             dst[j*dst_stride + i] = src[(j+yoffset)*src_stride + i+xoffset];
yading@10:         }else{
yading@10:             dst[j*dst_stride + i] = 0;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void cmv_decode_inter(CmvContext *s, AVFrame *frame, const uint8_t *buf,
yading@10:                              const uint8_t *buf_end)
yading@10: {
yading@10:     const uint8_t *raw = buf + (s->avctx->width*s->avctx->height/16);
yading@10:     int x,y,i;
yading@10: 
yading@10:     i = 0;
yading@10:     for(y=0; y<s->avctx->height/4; y++)
yading@10:     for(x=0; x<s->avctx->width/4 && buf_end - buf > i; x++) {
yading@10:         if (buf[i]==0xFF) {
yading@10:             unsigned char *dst = frame->data[0] + (y*4)*frame->linesize[0] + x*4;
yading@10:             if (raw+16<buf_end && *raw==0xFF) { /* intra */
yading@10:                 raw++;
yading@10:                 memcpy(dst, raw, 4);
yading@10:                 memcpy(dst +     frame->linesize[0], raw+4, 4);
yading@10:                 memcpy(dst + 2 * frame->linesize[0], raw+8, 4);
yading@10:                 memcpy(dst + 3 * frame->linesize[0], raw+12, 4);
yading@10:                 raw+=16;
yading@10:             }else if(raw<buf_end) {  /* inter using second-last frame as reference */
yading@10:                 int xoffset = (*raw & 0xF) - 7;
yading@10:                 int yoffset = ((*raw >> 4)) - 7;
yading@10:                 if (s->last2_frame->data[0])
yading@10:                     cmv_motcomp(frame->data[0], frame->linesize[0],
yading@10:                                 s->last2_frame->data[0], s->last2_frame->linesize[0],
yading@10:                                 x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
yading@10:                 raw++;
yading@10:             }
yading@10:         }else{  /* inter using last frame as reference */
yading@10:             int xoffset = (buf[i] & 0xF) - 7;
yading@10:             int yoffset = ((buf[i] >> 4)) - 7;
yading@10:             if (s->last_frame->data[0])
yading@10:                 cmv_motcomp(frame->data[0], frame->linesize[0],
yading@10:                           s->last_frame->data[0], s->last_frame->linesize[0],
yading@10:                           x*4, y*4, xoffset, yoffset, s->avctx->width, s->avctx->height);
yading@10:         }
yading@10:         i++;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void cmv_process_header(CmvContext *s, const uint8_t *buf, const uint8_t *buf_end)
yading@10: {
yading@10:     int pal_start, pal_count, i;
yading@10: 
yading@10:     if(buf_end - buf < 16) {
yading@10:         av_log(s->avctx, AV_LOG_WARNING, "truncated header\n");
yading@10:         return;
yading@10:     }
yading@10: 
yading@10:     s->width  = AV_RL16(&buf[4]);
yading@10:     s->height = AV_RL16(&buf[6]);
yading@10:     if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
yading@10:         avcodec_set_dimensions(s->avctx, s->width, s->height);
yading@10:         av_frame_unref(s->last_frame);
yading@10:         av_frame_unref(s->last2_frame);
yading@10:     }
yading@10: 
yading@10:     s->avctx->time_base.num = 1;
yading@10:     s->avctx->time_base.den = AV_RL16(&buf[10]);
yading@10: 
yading@10:     pal_start = AV_RL16(&buf[12]);
yading@10:     pal_count = AV_RL16(&buf[14]);
yading@10: 
yading@10:     buf += 16;
yading@10:     for (i=pal_start; i<pal_start+pal_count && i<AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
yading@10:         s->palette[i] = 0xFFU << 24 | AV_RB24(buf);
yading@10:         buf += 3;
yading@10:     }
yading@10: }
yading@10: 
yading@10: #define EA_PREAMBLE_SIZE 8
yading@10: #define MVIh_TAG MKTAG('M', 'V', 'I', 'h')
yading@10: 
yading@10: static int cmv_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame,
yading@10:                             AVPacket *avpkt)
yading@10: {
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size = avpkt->size;
yading@10:     CmvContext *s = avctx->priv_data;
yading@10:     const uint8_t *buf_end = buf + buf_size;
yading@10:     AVFrame *frame = data;
yading@10:     int ret;
yading@10: 
yading@10:     if (buf_end - buf < EA_PREAMBLE_SIZE)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     if (AV_RL32(buf)==MVIh_TAG||AV_RB32(buf)==MVIh_TAG) {
yading@10:         unsigned size = AV_RL32(buf + 4);
yading@10:         cmv_process_header(s, buf+EA_PREAMBLE_SIZE, buf_end);
yading@10:         if (size > buf_end - buf - EA_PREAMBLE_SIZE)
yading@10:             return -1;
yading@10:         buf += size;
yading@10:     }
yading@10: 
yading@10:     if (av_image_check_size(s->width, s->height, 0, s->avctx))
yading@10:         return -1;
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
yading@10: 
yading@10:     buf += EA_PREAMBLE_SIZE;
yading@10:     if ((buf[0]&1)) {  // subtype
yading@10:         cmv_decode_inter(s, frame, buf+2, buf_end);
yading@10:         frame->key_frame = 0;
yading@10:         frame->pict_type = AV_PICTURE_TYPE_P;
yading@10:     }else{
yading@10:         frame->key_frame = 1;
yading@10:         frame->pict_type = AV_PICTURE_TYPE_I;
yading@10:         cmv_decode_intra(s, frame, buf+2, buf_end);
yading@10:     }
yading@10: 
yading@10:     av_frame_unref(s->last2_frame);
yading@10:     av_frame_move_ref(s->last2_frame, s->last_frame);
yading@10:     if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int cmv_decode_end(AVCodecContext *avctx){
yading@10:     CmvContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&s->last_frame);
yading@10:     av_frame_free(&s->last2_frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_eacmv_decoder = {
yading@10:     .name           = "eacmv",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_CMV,
yading@10:     .priv_data_size = sizeof(CmvContext),
yading@10:     .init           = cmv_decode_init,
yading@10:     .close          = cmv_decode_end,
yading@10:     .decode         = cmv_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts CMV video"),
yading@10: };