/*
  * Bethsoft VID format Demuxer
  * Copyright (c) 2007 Nicholas Tung
  *
  * 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
  */
 
 /**

  * @file

  * @brief Bethesda Softworks VID (.vid) file demuxer
  * @author Nicholas Tung [ntung (at. ntung com] (2007-03)

  * @see http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
  * @see http://www.svatopluk.com/andux/docs/dfvid.html

  */
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/intreadwrite.h"

 #include "avformat.h"

 #include "internal.h"

 #include "libavcodec/bethsoftvideo.h"

 #define BVID_PALETTE_SIZE 3 * 256
 

 #define DEFAULT_SAMPLE_RATE 11111
 

 typedef struct BVID_DemuxContext
 {
     int nframes;

     int sample_rate;        /**< audio sample rate */

     int width;              /**< video width       */
     int height;             /**< video height      */

     /** delay value between frames, added to individual frame delay.
      * custom units, which will be added to other custom units (~=16ms according
      * to free, unofficial documentation) */
     int bethsoft_global_delay;

     int video_index;        /**< video stream index */
     int audio_index;        /**< audio stream index */

     uint8_t *palette;

 
     int is_finished;
 
 } BVID_DemuxContext;
 
 static int vid_probe(AVProbeData *p)
 {

     // little-endian VID tag, file starts with "VID\0"

     if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))

         return 0;
 

     if (p->buf[4] != 2)
         return AVPROBE_SCORE_MAX / 4;
 

     return AVPROBE_SCORE_MAX;
 }
 

 static int vid_read_header(AVFormatContext *s)

 {

     BVID_DemuxContext *vid = s->priv_data;

     AVIOContext *pb = s->pb;

 
     /* load main header. Contents:
     *    bytes: 'V' 'I' 'D'
     *    int16s: always_512, nframes, width, height, delay, always_14
     */

     avio_skip(pb, 5);

     vid->nframes = avio_rl16(pb);

     vid->width   = avio_rl16(pb);
     vid->height  = avio_rl16(pb);

     vid->bethsoft_global_delay = avio_rl16(pb);
     avio_rl16(pb);

     // wait until the first packet to create each stream
     vid->video_index = -1;

     vid->audio_index = -1;

     vid->sample_rate = DEFAULT_SAMPLE_RATE;

     s->ctx_flags |= AVFMTCTX_NOHEADER;

 
     return 0;
 }
 
 #define BUFFER_PADDING_SIZE 1000

 static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,

                       uint8_t block_type, AVFormatContext *s)

 {
     uint8_t * vidbuf_start = NULL;
     int vidbuf_nbytes = 0;

     int code;

     int bytes_copied = 0;

     int position, duration, npixels;

     unsigned int vidbuf_capacity;

     int ret = 0;

     AVStream *st;
 
     if (vid->video_index < 0) {
         st = avformat_new_stream(s, NULL);
         if (!st)
             return AVERROR(ENOMEM);
         vid->video_index = st->index;
         if (vid->audio_index < 0) {

             avpriv_request_sample(s, "Using default video time base since "
                                   "having no audio packet before the first "
                                   "video packet");

         }
         avpriv_set_pts_info(st, 64, 185, vid->sample_rate);
         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

         st->codec->codec_id   = AV_CODEC_ID_BETHSOFTVID;

         st->codec->width      = vid->width;
         st->codec->height     = vid->height;
     }
     st      = s->streams[vid->video_index];
     npixels = st->codec->width * st->codec->height;

 
     vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);

     if(!vidbuf_start)

         return AVERROR(ENOMEM);

 
     // save the file position for the packet, include block type

     position = avio_tell(pb) - 1;

 
     vidbuf_start[vidbuf_nbytes++] = block_type;
 

     // get the current packet duration
     duration = vid->bethsoft_global_delay + avio_rl16(pb);

 
     // set the y offset if it exists (decoder header data should be in data section)

     if(block_type == VIDEO_YOFF_P_FRAME){

         if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2) {
             ret = AVERROR(EIO);

             goto fail;

         }

         vidbuf_nbytes += 2;
     }
 

     do{

         vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);

         if(!vidbuf_start)

             return AVERROR(ENOMEM);

         code = avio_r8(pb);

         vidbuf_start[vidbuf_nbytes++] = code;

         if(code >= 0x80){ // rle sequence

             if(block_type == VIDEO_I_FRAME)

                 vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);

         } else if(code){ // plain sequence

             if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code) {
                 ret = AVERROR(EIO);

                 goto fail;

             }

             vidbuf_nbytes += code;

         }

         bytes_copied += code & 0x7F;

         if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied

             // may contain a 0 byte even if read all pixels

             if(avio_r8(pb))

                 avio_seek(pb, -1, SEEK_CUR);

             break;
         }

         if (bytes_copied > npixels) {
             ret = AVERROR_INVALIDDATA;

             goto fail;

         }

     } while(code);

 
     // copy data into packet

     if ((ret = av_new_packet(pkt, vidbuf_nbytes)) < 0)

         goto fail;

     memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
     av_free(vidbuf_start);
 
     pkt->pos = position;

     pkt->stream_index = vid->video_index;

     pkt->duration = duration;

     if (block_type == VIDEO_I_FRAME)
         pkt->flags |= AV_PKT_FLAG_KEY;

     /* if there is a new palette available, add it to packet side data */
     if (vid->palette) {
         uint8_t *pdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
                                                  BVID_PALETTE_SIZE);

         if (pdata)
             memcpy(pdata, vid->palette, BVID_PALETTE_SIZE);

         av_freep(&vid->palette);
     }

 
     vid->nframes--;  // used to check if all the frames were read

     return 0;

 fail:
     av_free(vidbuf_start);

     return ret;

 }
 
 static int vid_read_packet(AVFormatContext *s,
                            AVPacket *pkt)
 {

     BVID_DemuxContext *vid = s->priv_data;

     AVIOContext *pb = s->pb;

     unsigned char block_type;

     int audio_length;
     int ret_value;
 

     if(vid->is_finished || url_feof(pb))

         return AVERROR_EOF;

     block_type = avio_r8(pb);

     switch(block_type){

         case PALETTE_BLOCK:

             if (vid->palette) {
                 av_log(s, AV_LOG_WARNING, "discarding unused palette\n");
                 av_freep(&vid->palette);
             }
             vid->palette = av_malloc(BVID_PALETTE_SIZE);
             if (!vid->palette)
                 return AVERROR(ENOMEM);
             if (avio_read(pb, vid->palette, BVID_PALETTE_SIZE) != BVID_PALETTE_SIZE) {
                 av_freep(&vid->palette);

                 return AVERROR(EIO);

             }

             return vid_read_packet(s, pkt);

 
         case FIRST_AUDIO_BLOCK:

             avio_rl16(pb);

             // soundblaster DAC used for sample rate, as on specification page (link above)

             vid->sample_rate = 1000000 / (256 - avio_r8(pb));

         case AUDIO_BLOCK:

             if (vid->audio_index < 0) {
                 AVStream *st = avformat_new_stream(s, NULL);
                 if (!st)
                     return AVERROR(ENOMEM);
                 vid->audio_index                 = st->index;
                 st->codec->codec_type            = AVMEDIA_TYPE_AUDIO;

                 st->codec->codec_id              = AV_CODEC_ID_PCM_U8;

                 st->codec->channels              = 1;

                 st->codec->channel_layout        = AV_CH_LAYOUT_MONO;

                 st->codec->bits_per_coded_sample = 8;
                 st->codec->sample_rate           = vid->sample_rate;
                 st->codec->bit_rate              = 8 * st->codec->sample_rate;
                 st->start_time                   = 0;
                 avpriv_set_pts_info(st, 64, 1, vid->sample_rate);
             }

             audio_length = avio_rl16(pb);

             if ((ret_value = av_get_packet(pb, pkt, audio_length)) != audio_length) {
                 if (ret_value < 0)
                     return ret_value;
                 av_log(s, AV_LOG_ERROR, "incomplete audio block\n");
                 return AVERROR(EIO);
             }

             pkt->stream_index = vid->audio_index;
             pkt->duration     = audio_length;

             pkt->flags |= AV_PKT_FLAG_KEY;

             return 0;

         case VIDEO_P_FRAME:
         case VIDEO_YOFF_P_FRAME:
         case VIDEO_I_FRAME:

             return read_frame(vid, pb, pkt, block_type, s);

         case EOF_BLOCK:

             if(vid->nframes != 0)
                 av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
             vid->is_finished = 1;

             return AVERROR(EIO);

         default:
             av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",

                    block_type, block_type, block_type);
             return AVERROR_INVALIDDATA;

     }
 }
 

 static int vid_read_close(AVFormatContext *s)
 {
     BVID_DemuxContext *vid = s->priv_data;
     av_freep(&vid->palette);
     return 0;
 }
 

 AVInputFormat ff_bethsoftvid_demuxer = {

     .name           = "bethsoftvid",

     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID"),

     .priv_data_size = sizeof(BVID_DemuxContext),
     .read_probe     = vid_probe,
     .read_header    = vid_read_header,
     .read_packet    = vid_read_packet,

     .read_close     = vid_read_close,

 };