/*
  * AVRn decoder
  * Copyright (c) 2012 Michael Niedermayer
  *
  * 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 "internal.h"

 #include "mjpeg.h"
 #include "mjpegdec.h"

 #include "libavutil/imgutils.h"

 
 typedef struct {

     AVCodecContext *mjpeg_avctx;

     int is_mjpeg;

     int interlace;

     int tff;
 } AVRnContext;
 
 static av_cold int init(AVCodecContext *avctx)
 {
     AVRnContext *a = avctx->priv_data;

     int ret;

 
     // Support "Resolution 1:1" for Avid AVI Codec
     a->is_mjpeg = avctx->extradata_size < 31 || memcmp(&avctx->extradata[28], "1:1", 3);
 

     if(!a->is_mjpeg && avctx->lowres) {
         av_log(avctx, AV_LOG_ERROR, "lowres is not possible with rawvideo\n");
         return AVERROR(EINVAL);
     }
 

     if(a->is_mjpeg) {
         AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_MJPEG);
         AVDictionary *thread_opt = NULL;
         if (!codec) {
             av_log(avctx, AV_LOG_ERROR, "MJPEG codec not found\n");
             return AVERROR_DECODER_NOT_FOUND;
         }
 
         a->mjpeg_avctx = avcodec_alloc_context3(codec);
 
         av_dict_set(&thread_opt, "threads", "1", 0); // Is this needed ?
         a->mjpeg_avctx->refcounted_frames = 1;
         a->mjpeg_avctx->flags = avctx->flags;
         a->mjpeg_avctx->idct_algo = avctx->idct_algo;
         a->mjpeg_avctx->lowres = avctx->lowres;
         a->mjpeg_avctx->width = avctx->width;
         a->mjpeg_avctx->height = avctx->height;
 
         if ((ret = ff_codec_open2_recursive(a->mjpeg_avctx, codec, &thread_opt)) < 0) {
             av_log(avctx, AV_LOG_ERROR, "MJPEG codec failed to open\n");
         }
         av_dict_free(&thread_opt);
 
         return ret;
     }

     if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
         return ret;

     avctx->pix_fmt = AV_PIX_FMT_UYVY422;

 
     if(avctx->extradata_size >= 9 && avctx->extradata[4]+28 < avctx->extradata_size) {
         int ndx = avctx->extradata[4] + 4;
         a->interlace = !memcmp(avctx->extradata + ndx, "1:1(", 4);
         if(a->interlace) {
             a->tff = avctx->extradata[ndx + 24] == 1;
         }
     }
 
     return 0;
 }
 

 static av_cold int end(AVCodecContext *avctx)

 {
     AVRnContext *a = avctx->priv_data;
 

     avcodec_close(a->mjpeg_avctx);
     av_freep(&a->mjpeg_avctx);

 
     return 0;

 }
 

 static int decode_frame(AVCodecContext *avctx, void *data,
                         int *got_frame, AVPacket *avpkt)

 {
     AVRnContext *a = avctx->priv_data;

     AVFrame *p = data;

     const uint8_t *buf = avpkt->data;
     int buf_size       = avpkt->size;

     int y, ret, true_height;

     if(a->is_mjpeg) {
         ret = avcodec_decode_video2(a->mjpeg_avctx, data, got_frame, avpkt);
 
         if (ret >= 0 && *got_frame && avctx->width <= p->width && avctx->height <= p->height) {
             int shift = p->height - avctx->height;
             int subsample_h, subsample_v;
 

             av_pix_fmt_get_chroma_sub_sample(p->format, &subsample_h, &subsample_v);

 
             p->data[0] += p->linesize[0] * shift;
             if (p->data[2]) {
                 p->data[1] += p->linesize[1] * (shift>>subsample_v);
                 p->data[2] += p->linesize[2] * (shift>>subsample_v);
             }
 
             p->width  = avctx->width;
             p->height = avctx->height;
         }
         avctx->pix_fmt = a->mjpeg_avctx->pix_fmt;
         return ret;
     }

     true_height    = buf_size / (2*avctx->width);

 
     if(buf_size < 2*avctx->width * avctx->height) {
         av_log(avctx, AV_LOG_ERROR, "packet too small\n");
         return AVERROR_INVALIDDATA;
     }
 

     if ((ret = ff_get_buffer(avctx, p, 0)) < 0)

         return ret;

     p->pict_type= AV_PICTURE_TYPE_I;
     p->key_frame= 1;
 
     if(a->interlace) {
         buf += (true_height - avctx->height)*avctx->width;
         for(y = 0; y < avctx->height-1; y+=2) {
             memcpy(p->data[0] + (y+ a->tff)*p->linesize[0], buf                             , 2*avctx->width);
             memcpy(p->data[0] + (y+!a->tff)*p->linesize[0], buf + avctx->width*true_height+4, 2*avctx->width);
             buf += 2*avctx->width;
         }
     } else {

         buf += (true_height - avctx->height)*avctx->width*2;

         for(y = 0; y < avctx->height; y++) {
             memcpy(p->data[0] + y*p->linesize[0], buf, 2*avctx->width);
             buf += 2*avctx->width;
         }
     }
 

     *got_frame      = 1;

     return buf_size;
 }
 
 AVCodec ff_avrn_decoder = {

     .name           = "avrn",

     .long_name      = NULL_IF_CONFIG_SMALL("Avid AVI Codec"),

     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_AVRN,
     .priv_data_size = sizeof(AVRnContext),
     .init           = init,
     .close          = end,
     .decode         = decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

     .max_lowres     = 3,

 };