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  1. /*
  2.  * Interplay MVE File Demuxer
  3.  * Copyright (c) 2003 The FFmpeg Project
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * Interplay MVE file demuxer
  25.  * by Mike Melanson (melanson@pcisys.net)
  26.  * For more information regarding the Interplay MVE file format, visit:
  27.  *   http://www.pcisys.net/~melanson/codecs/
  28.  * The aforementioned site also contains a command line utility for parsing
  29.  * IP MVE files so that you can get a good idea of the typical structure of
  30.  * such files. This demuxer is not the best example to use if you are trying
  31.  * to write your own as it uses a rather roundabout approach for splitting
  32.  * up and sending out the chunks.
  33.  */
  34.  
  35. #include "libavutil/channel_layout.h"
  36. #include "libavutil/intreadwrite.h"
  37. #include "avformat.h"
  38. #include "internal.h"
  39.  
  40. #define CHUNK_PREAMBLE_SIZE 4
  41. #define OPCODE_PREAMBLE_SIZE 4
  42.  
  43. #define CHUNK_INIT_AUDIO   0x0000
  44. #define CHUNK_AUDIO_ONLY   0x0001
  45. #define CHUNK_INIT_VIDEO   0x0002
  46. #define CHUNK_VIDEO        0x0003
  47. #define CHUNK_SHUTDOWN     0x0004
  48. #define CHUNK_END          0x0005
  49. /* these last types are used internally */
  50. #define CHUNK_DONE         0xFFFC
  51. #define CHUNK_NOMEM        0xFFFD
  52. #define CHUNK_EOF          0xFFFE
  53. #define CHUNK_BAD          0xFFFF
  54.  
  55. #define OPCODE_END_OF_STREAM           0x00
  56. #define OPCODE_END_OF_CHUNK            0x01
  57. #define OPCODE_CREATE_TIMER            0x02
  58. #define OPCODE_INIT_AUDIO_BUFFERS      0x03
  59. #define OPCODE_START_STOP_AUDIO        0x04
  60. #define OPCODE_INIT_VIDEO_BUFFERS      0x05
  61. #define OPCODE_UNKNOWN_06              0x06
  62. #define OPCODE_SEND_BUFFER             0x07
  63. #define OPCODE_AUDIO_FRAME             0x08
  64. #define OPCODE_SILENCE_FRAME           0x09
  65. #define OPCODE_INIT_VIDEO_MODE         0x0A
  66. #define OPCODE_CREATE_GRADIENT         0x0B
  67. #define OPCODE_SET_PALETTE             0x0C
  68. #define OPCODE_SET_PALETTE_COMPRESSED  0x0D
  69. #define OPCODE_UNKNOWN_0E              0x0E
  70. #define OPCODE_SET_DECODING_MAP        0x0F
  71. #define OPCODE_UNKNOWN_10              0x10
  72. #define OPCODE_VIDEO_DATA              0x11
  73. #define OPCODE_UNKNOWN_12              0x12
  74. #define OPCODE_UNKNOWN_13              0x13
  75. #define OPCODE_UNKNOWN_14              0x14
  76. #define OPCODE_UNKNOWN_15              0x15
  77.  
  78. #define PALETTE_COUNT 256
  79.  
  80. typedef struct IPMVEContext {
  81.     AVFormatContext *avf;
  82.     unsigned char *buf;
  83.     int buf_size;
  84.  
  85.     uint64_t frame_pts_inc;
  86.  
  87.     unsigned int video_bpp;
  88.     unsigned int video_width;
  89.     unsigned int video_height;
  90.     int64_t video_pts;
  91.     uint32_t     palette[256];
  92.     int          has_palette;
  93.     int          changed;
  94.  
  95.     unsigned int audio_bits;
  96.     unsigned int audio_channels;
  97.     unsigned int audio_sample_rate;
  98.     enum AVCodecID audio_type;
  99.     unsigned int audio_frame_count;
  100.  
  101.     int video_stream_index;
  102.     int audio_stream_index;
  103.  
  104.     int64_t audio_chunk_offset;
  105.     int audio_chunk_size;
  106.     int64_t video_chunk_offset;
  107.     int video_chunk_size;
  108.     int64_t decode_map_chunk_offset;
  109.     int decode_map_chunk_size;
  110.  
  111.     int64_t next_chunk_offset;
  112.  
  113. } IPMVEContext;
  114.  
  115. static int load_ipmovie_packet(IPMVEContext *s, AVIOContext *pb,
  116.     AVPacket *pkt) {
  117.  
  118.     int chunk_type;
  119.  
  120.     if (s->audio_chunk_offset && s->audio_channels && s->audio_bits) {
  121.         if (s->audio_type == AV_CODEC_ID_NONE) {
  122.             av_log(NULL, AV_LOG_ERROR, "Can not read audio packet before"
  123.                    "audio codec is known\n");
  124.                 return CHUNK_BAD;
  125.         }
  126.  
  127.         /* adjust for PCM audio by skipping chunk header */
  128.         if (s->audio_type != AV_CODEC_ID_INTERPLAY_DPCM) {
  129.             s->audio_chunk_offset += 6;
  130.             s->audio_chunk_size -= 6;
  131.         }
  132.  
  133.         avio_seek(pb, s->audio_chunk_offset, SEEK_SET);
  134.         s->audio_chunk_offset = 0;
  135.  
  136.         if (s->audio_chunk_size != av_get_packet(pb, pkt, s->audio_chunk_size))
  137.             return CHUNK_EOF;
  138.  
  139.         pkt->stream_index = s->audio_stream_index;
  140.         pkt->pts = s->audio_frame_count;
  141.  
  142.         /* audio frame maintenance */
  143.         if (s->audio_type != AV_CODEC_ID_INTERPLAY_DPCM)
  144.             s->audio_frame_count +=
  145.             (s->audio_chunk_size / s->audio_channels / (s->audio_bits / 8));
  146.         else
  147.             s->audio_frame_count +=
  148.                 (s->audio_chunk_size - 6 - s->audio_channels) / s->audio_channels;
  149.  
  150.         av_log(NULL, AV_LOG_TRACE, "sending audio frame with pts %"PRId64" (%d audio frames)\n",
  151.                 pkt->pts, s->audio_frame_count);
  152.  
  153.         chunk_type = CHUNK_VIDEO;
  154.  
  155.     } else if (s->decode_map_chunk_offset) {
  156.  
  157.         /* send both the decode map and the video data together */
  158.  
  159.         if (av_new_packet(pkt, s->decode_map_chunk_size + s->video_chunk_size))
  160.             return CHUNK_NOMEM;
  161.  
  162.         if (s->has_palette) {
  163.             uint8_t *pal;
  164.  
  165.             pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
  166.                                           AVPALETTE_SIZE);
  167.             if (pal) {
  168.                 memcpy(pal, s->palette, AVPALETTE_SIZE);
  169.                 s->has_palette = 0;
  170.             }
  171.         }
  172.  
  173.         if (s->changed) {
  174.             ff_add_param_change(pkt, 0, 0, 0, s->video_width, s->video_height);
  175.             s->changed = 0;
  176.         }
  177.         pkt->pos= s->decode_map_chunk_offset;
  178.         avio_seek(pb, s->decode_map_chunk_offset, SEEK_SET);
  179.         s->decode_map_chunk_offset = 0;
  180.  
  181.         if (avio_read(pb, pkt->data, s->decode_map_chunk_size) !=
  182.             s->decode_map_chunk_size) {
  183.             av_free_packet(pkt);
  184.             return CHUNK_EOF;
  185.         }
  186.  
  187.         avio_seek(pb, s->video_chunk_offset, SEEK_SET);
  188.         s->video_chunk_offset = 0;
  189.  
  190.         if (avio_read(pb, pkt->data + s->decode_map_chunk_size,
  191.             s->video_chunk_size) != s->video_chunk_size) {
  192.             av_free_packet(pkt);
  193.             return CHUNK_EOF;
  194.         }
  195.  
  196.         pkt->stream_index = s->video_stream_index;
  197.         pkt->pts = s->video_pts;
  198.  
  199.         av_log(NULL, AV_LOG_TRACE, "sending video frame with pts %"PRId64"\n", pkt->pts);
  200.  
  201.         s->video_pts += s->frame_pts_inc;
  202.  
  203.         chunk_type = CHUNK_VIDEO;
  204.  
  205.     } else {
  206.  
  207.         avio_seek(pb, s->next_chunk_offset, SEEK_SET);
  208.         chunk_type = CHUNK_DONE;
  209.  
  210.     }
  211.  
  212.     return chunk_type;
  213. }
  214.  
  215. static int init_audio(AVFormatContext *s)
  216. {
  217.     IPMVEContext *ipmovie = s->priv_data;
  218.     AVStream *st = avformat_new_stream(s, NULL);
  219.     if (!st)
  220.         return AVERROR(ENOMEM);
  221.     avpriv_set_pts_info(st, 32, 1, ipmovie->audio_sample_rate);
  222.     ipmovie->audio_stream_index = st->index;
  223.     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  224.     st->codec->codec_id = ipmovie->audio_type;
  225.     st->codec->codec_tag = 0;  /* no tag */
  226.     st->codec->channels = ipmovie->audio_channels;
  227.     st->codec->channel_layout = st->codec->channels == 1 ? AV_CH_LAYOUT_MONO :
  228.                                                             AV_CH_LAYOUT_STEREO;
  229.     st->codec->sample_rate = ipmovie->audio_sample_rate;
  230.     st->codec->bits_per_coded_sample = ipmovie->audio_bits;
  231.     st->codec->bit_rate = st->codec->channels * st->codec->sample_rate *
  232.         st->codec->bits_per_coded_sample;
  233.     if (st->codec->codec_id == AV_CODEC_ID_INTERPLAY_DPCM)
  234.         st->codec->bit_rate /= 2;
  235.     st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
  236.  
  237.     return 0;
  238. }
  239.  
  240. /* This function loads and processes a single chunk in an IP movie file.
  241.  * It returns the type of chunk that was processed. */
  242. static int process_ipmovie_chunk(IPMVEContext *s, AVIOContext *pb,
  243.     AVPacket *pkt)
  244. {
  245.     unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
  246.     int chunk_type;
  247.     int chunk_size;
  248.     unsigned char opcode_preamble[OPCODE_PREAMBLE_SIZE];
  249.     unsigned char opcode_type;
  250.     unsigned char opcode_version;
  251.     int opcode_size;
  252.     unsigned char scratch[1024];
  253.     int i, j;
  254.     int first_color, last_color;
  255.     int audio_flags;
  256.     unsigned char r, g, b;
  257.     unsigned int width, height;
  258.  
  259.     /* see if there are any pending packets */
  260.     chunk_type = load_ipmovie_packet(s, pb, pkt);
  261.     if (chunk_type != CHUNK_DONE)
  262.         return chunk_type;
  263.  
  264.     /* read the next chunk, wherever the file happens to be pointing */
  265.     if (avio_feof(pb))
  266.         return CHUNK_EOF;
  267.     if (avio_read(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
  268.         CHUNK_PREAMBLE_SIZE)
  269.         return CHUNK_BAD;
  270.     chunk_size = AV_RL16(&chunk_preamble[0]);
  271.     chunk_type = AV_RL16(&chunk_preamble[2]);
  272.  
  273.     av_log(NULL, AV_LOG_TRACE, "chunk type 0x%04X, 0x%04X bytes: ", chunk_type, chunk_size);
  274.  
  275.     switch (chunk_type) {
  276.  
  277.     case CHUNK_INIT_AUDIO:
  278.         av_log(NULL, AV_LOG_TRACE, "initialize audio\n");
  279.         break;
  280.  
  281.     case CHUNK_AUDIO_ONLY:
  282.         av_log(NULL, AV_LOG_TRACE, "audio only\n");
  283.         break;
  284.  
  285.     case CHUNK_INIT_VIDEO:
  286.         av_log(NULL, AV_LOG_TRACE, "initialize video\n");
  287.         break;
  288.  
  289.     case CHUNK_VIDEO:
  290.         av_log(NULL, AV_LOG_TRACE, "video (and audio)\n");
  291.         break;
  292.  
  293.     case CHUNK_SHUTDOWN:
  294.         av_log(NULL, AV_LOG_TRACE, "shutdown\n");
  295.         break;
  296.  
  297.     case CHUNK_END:
  298.         av_log(NULL, AV_LOG_TRACE, "end\n");
  299.         break;
  300.  
  301.     default:
  302.         av_log(NULL, AV_LOG_TRACE, "invalid chunk\n");
  303.         chunk_type = CHUNK_BAD;
  304.         break;
  305.  
  306.     }
  307.  
  308.     while ((chunk_size > 0) && (chunk_type != CHUNK_BAD)) {
  309.  
  310.         /* read the next chunk, wherever the file happens to be pointing */
  311.         if (avio_feof(pb)) {
  312.             chunk_type = CHUNK_EOF;
  313.             break;
  314.         }
  315.         if (avio_read(pb, opcode_preamble, CHUNK_PREAMBLE_SIZE) !=
  316.             CHUNK_PREAMBLE_SIZE) {
  317.             chunk_type = CHUNK_BAD;
  318.             break;
  319.         }
  320.  
  321.         opcode_size = AV_RL16(&opcode_preamble[0]);
  322.         opcode_type = opcode_preamble[2];
  323.         opcode_version = opcode_preamble[3];
  324.  
  325.         chunk_size -= OPCODE_PREAMBLE_SIZE;
  326.         chunk_size -= opcode_size;
  327.         if (chunk_size < 0) {
  328.             av_log(NULL, AV_LOG_TRACE, "chunk_size countdown just went negative\n");
  329.             chunk_type = CHUNK_BAD;
  330.             break;
  331.         }
  332.  
  333.         av_log(NULL, AV_LOG_TRACE, "  opcode type %02X, version %d, 0x%04X bytes: ",
  334.                 opcode_type, opcode_version, opcode_size);
  335.         switch (opcode_type) {
  336.  
  337.         case OPCODE_END_OF_STREAM:
  338.             av_log(NULL, AV_LOG_TRACE, "end of stream\n");
  339.             avio_skip(pb, opcode_size);
  340.             break;
  341.  
  342.         case OPCODE_END_OF_CHUNK:
  343.             av_log(NULL, AV_LOG_TRACE, "end of chunk\n");
  344.             avio_skip(pb, opcode_size);
  345.             break;
  346.  
  347.         case OPCODE_CREATE_TIMER:
  348.             av_log(NULL, AV_LOG_TRACE, "create timer\n");
  349.             if ((opcode_version > 0) || (opcode_size != 6)) {
  350.                 av_log(NULL, AV_LOG_TRACE, "bad create_timer opcode\n");
  351.                 chunk_type = CHUNK_BAD;
  352.                 break;
  353.             }
  354.             if (avio_read(pb, scratch, opcode_size) !=
  355.                 opcode_size) {
  356.                 chunk_type = CHUNK_BAD;
  357.                 break;
  358.             }
  359.             s->frame_pts_inc = ((uint64_t)AV_RL32(&scratch[0])) * AV_RL16(&scratch[4]);
  360.             av_log(NULL, AV_LOG_TRACE, "  %.2f frames/second (timer div = %d, subdiv = %d)\n",
  361.                     1000000.0 / s->frame_pts_inc, AV_RL32(&scratch[0]),
  362.                     AV_RL16(&scratch[4]));
  363.             break;
  364.  
  365.         case OPCODE_INIT_AUDIO_BUFFERS:
  366.             av_log(NULL, AV_LOG_TRACE, "initialize audio buffers\n");
  367.             if (opcode_version > 1 || opcode_size > 10 || opcode_size < 6) {
  368.                 av_log(NULL, AV_LOG_TRACE, "bad init_audio_buffers opcode\n");
  369.                 chunk_type = CHUNK_BAD;
  370.                 break;
  371.             }
  372.             if (avio_read(pb, scratch, opcode_size) !=
  373.                 opcode_size) {
  374.                 chunk_type = CHUNK_BAD;
  375.                 break;
  376.             }
  377.             s->audio_sample_rate = AV_RL16(&scratch[4]);
  378.             audio_flags = AV_RL16(&scratch[2]);
  379.             /* bit 0 of the flags: 0 = mono, 1 = stereo */
  380.             s->audio_channels = (audio_flags & 1) + 1;
  381.             /* bit 1 of the flags: 0 = 8 bit, 1 = 16 bit */
  382.             s->audio_bits = (((audio_flags >> 1) & 1) + 1) * 8;
  383.             /* bit 2 indicates compressed audio in version 1 opcode */
  384.             if ((opcode_version == 1) && (audio_flags & 0x4))
  385.                 s->audio_type = AV_CODEC_ID_INTERPLAY_DPCM;
  386.             else if (s->audio_bits == 16)
  387.                 s->audio_type = AV_CODEC_ID_PCM_S16LE;
  388.             else
  389.                 s->audio_type = AV_CODEC_ID_PCM_U8;
  390.             av_log(NULL, AV_LOG_TRACE, "audio: %d bits, %d Hz, %s, %s format\n",
  391.                     s->audio_bits, s->audio_sample_rate,
  392.                     (s->audio_channels == 2) ? "stereo" : "mono",
  393.                     (s->audio_type == AV_CODEC_ID_INTERPLAY_DPCM) ?
  394.                     "Interplay audio" : "PCM");
  395.             break;
  396.  
  397.         case OPCODE_START_STOP_AUDIO:
  398.             av_log(NULL, AV_LOG_TRACE, "start/stop audio\n");
  399.             avio_skip(pb, opcode_size);
  400.             break;
  401.  
  402.         case OPCODE_INIT_VIDEO_BUFFERS:
  403.             av_log(NULL, AV_LOG_TRACE, "initialize video buffers\n");
  404.             if ((opcode_version > 2) || (opcode_size > 8) || opcode_size < 4
  405.                 || opcode_version == 2 && opcode_size < 8
  406.             ) {
  407.                 av_log(NULL, AV_LOG_TRACE, "bad init_video_buffers opcode\n");
  408.                 chunk_type = CHUNK_BAD;
  409.                 break;
  410.             }
  411.             if (avio_read(pb, scratch, opcode_size) !=
  412.                 opcode_size) {
  413.                 chunk_type = CHUNK_BAD;
  414.                 break;
  415.             }
  416.             width  = AV_RL16(&scratch[0]) * 8;
  417.             height = AV_RL16(&scratch[2]) * 8;
  418.             if (width != s->video_width) {
  419.                 s->video_width = width;
  420.                 s->changed++;
  421.             }
  422.             if (height != s->video_height) {
  423.                 s->video_height = height;
  424.                 s->changed++;
  425.             }
  426.             if (opcode_version < 2 || !AV_RL16(&scratch[6])) {
  427.                 s->video_bpp = 8;
  428.             } else {
  429.                 s->video_bpp = 16;
  430.             }
  431.             av_log(NULL, AV_LOG_TRACE, "video resolution: %d x %d\n",
  432.                     s->video_width, s->video_height);
  433.             break;
  434.  
  435.         case OPCODE_UNKNOWN_06:
  436.         case OPCODE_UNKNOWN_0E:
  437.         case OPCODE_UNKNOWN_10:
  438.         case OPCODE_UNKNOWN_12:
  439.         case OPCODE_UNKNOWN_13:
  440.         case OPCODE_UNKNOWN_14:
  441.         case OPCODE_UNKNOWN_15:
  442.             av_log(NULL, AV_LOG_TRACE, "unknown (but documented) opcode %02X\n", opcode_type);
  443.             avio_skip(pb, opcode_size);
  444.             break;
  445.  
  446.         case OPCODE_SEND_BUFFER:
  447.             av_log(NULL, AV_LOG_TRACE, "send buffer\n");
  448.             avio_skip(pb, opcode_size);
  449.             break;
  450.  
  451.         case OPCODE_AUDIO_FRAME:
  452.             av_log(NULL, AV_LOG_TRACE, "audio frame\n");
  453.  
  454.             /* log position and move on for now */
  455.             s->audio_chunk_offset = avio_tell(pb);
  456.             s->audio_chunk_size = opcode_size;
  457.             avio_skip(pb, opcode_size);
  458.             break;
  459.  
  460.         case OPCODE_SILENCE_FRAME:
  461.             av_log(NULL, AV_LOG_TRACE, "silence frame\n");
  462.             avio_skip(pb, opcode_size);
  463.             break;
  464.  
  465.         case OPCODE_INIT_VIDEO_MODE:
  466.             av_log(NULL, AV_LOG_TRACE, "initialize video mode\n");
  467.             avio_skip(pb, opcode_size);
  468.             break;
  469.  
  470.         case OPCODE_CREATE_GRADIENT:
  471.             av_log(NULL, AV_LOG_TRACE, "create gradient\n");
  472.             avio_skip(pb, opcode_size);
  473.             break;
  474.  
  475.         case OPCODE_SET_PALETTE:
  476.             av_log(NULL, AV_LOG_TRACE, "set palette\n");
  477.             /* check for the logical maximum palette size
  478.              * (3 * 256 + 4 bytes) */
  479.             if (opcode_size > 0x304 || opcode_size < 4) {
  480.                 av_log(NULL, AV_LOG_TRACE, "demux_ipmovie: set_palette opcode with invalid size\n");
  481.                 chunk_type = CHUNK_BAD;
  482.                 break;
  483.             }
  484.             if (avio_read(pb, scratch, opcode_size) != opcode_size) {
  485.                 chunk_type = CHUNK_BAD;
  486.                 break;
  487.             }
  488.  
  489.             /* load the palette into internal data structure */
  490.             first_color = AV_RL16(&scratch[0]);
  491.             last_color = first_color + AV_RL16(&scratch[2]) - 1;
  492.             /* sanity check (since they are 16 bit values) */
  493.             if (   (first_color > 0xFF) || (last_color > 0xFF)
  494.                 || (last_color - first_color + 1)*3 + 4 > opcode_size) {
  495.                 av_log(NULL, AV_LOG_TRACE, "demux_ipmovie: set_palette indexes out of range (%d -> %d)\n",
  496.                     first_color, last_color);
  497.                 chunk_type = CHUNK_BAD;
  498.                 break;
  499.             }
  500.             j = 4;  /* offset of first palette data */
  501.             for (i = first_color; i <= last_color; i++) {
  502.                 /* the palette is stored as a 6-bit VGA palette, thus each
  503.                  * component is shifted up to a 8-bit range */
  504.                 r = scratch[j++] * 4;
  505.                 g = scratch[j++] * 4;
  506.                 b = scratch[j++] * 4;
  507.                 s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
  508.                 s->palette[i] |= s->palette[i] >> 6 & 0x30303;
  509.             }
  510.             s->has_palette = 1;
  511.             break;
  512.  
  513.         case OPCODE_SET_PALETTE_COMPRESSED:
  514.             av_log(NULL, AV_LOG_TRACE, "set palette compressed\n");
  515.             avio_skip(pb, opcode_size);
  516.             break;
  517.  
  518.         case OPCODE_SET_DECODING_MAP:
  519.             av_log(NULL, AV_LOG_TRACE, "set decoding map\n");
  520.  
  521.             /* log position and move on for now */
  522.             s->decode_map_chunk_offset = avio_tell(pb);
  523.             s->decode_map_chunk_size = opcode_size;
  524.             avio_skip(pb, opcode_size);
  525.             break;
  526.  
  527.         case OPCODE_VIDEO_DATA:
  528.             av_log(NULL, AV_LOG_TRACE, "set video data\n");
  529.  
  530.             /* log position and move on for now */
  531.             s->video_chunk_offset = avio_tell(pb);
  532.             s->video_chunk_size = opcode_size;
  533.             avio_skip(pb, opcode_size);
  534.             break;
  535.  
  536.         default:
  537.             av_log(NULL, AV_LOG_TRACE, "*** unknown opcode type\n");
  538.             chunk_type = CHUNK_BAD;
  539.             break;
  540.  
  541.         }
  542.     }
  543.  
  544.     if (s->avf->nb_streams == 1 && s->audio_type)
  545.         init_audio(s->avf);
  546.  
  547.     /* make a note of where the stream is sitting */
  548.     s->next_chunk_offset = avio_tell(pb);
  549.  
  550.     /* dispatch the first of any pending packets */
  551.     if ((chunk_type == CHUNK_VIDEO) || (chunk_type == CHUNK_AUDIO_ONLY))
  552.         chunk_type = load_ipmovie_packet(s, pb, pkt);
  553.  
  554.     return chunk_type;
  555. }
  556.  
  557. static const char signature[] = "Interplay MVE File\x1A\0\x1A";
  558.  
  559. static int ipmovie_probe(AVProbeData *p)
  560. {
  561.     const uint8_t *b = p->buf;
  562.     const uint8_t *b_end = p->buf + p->buf_size - sizeof(signature);
  563.     do {
  564.         if (b[0] == signature[0] && memcmp(b, signature, sizeof(signature)) == 0)
  565.             return AVPROBE_SCORE_MAX;
  566.         b++;
  567.     } while (b < b_end);
  568.  
  569.     return 0;
  570. }
  571.  
  572. static int ipmovie_read_header(AVFormatContext *s)
  573. {
  574.     IPMVEContext *ipmovie = s->priv_data;
  575.     AVIOContext *pb = s->pb;
  576.     AVPacket pkt;
  577.     AVStream *st;
  578.     unsigned char chunk_preamble[CHUNK_PREAMBLE_SIZE];
  579.     int chunk_type, i;
  580.     uint8_t signature_buffer[sizeof(signature)];
  581.  
  582.     ipmovie->avf = s;
  583.  
  584.     avio_read(pb, signature_buffer, sizeof(signature_buffer));
  585.     while (memcmp(signature_buffer, signature, sizeof(signature))) {
  586.         memmove(signature_buffer, signature_buffer + 1, sizeof(signature_buffer) - 1);
  587.         signature_buffer[sizeof(signature_buffer) - 1] = avio_r8(pb);
  588.         if (avio_feof(pb))
  589.             return AVERROR_EOF;
  590.     }
  591.     /* initialize private context members */
  592.     ipmovie->video_pts = ipmovie->audio_frame_count = 0;
  593.     ipmovie->audio_chunk_offset = ipmovie->video_chunk_offset =
  594.     ipmovie->decode_map_chunk_offset = 0;
  595.  
  596.     /* on the first read, this will position the stream at the first chunk */
  597.     ipmovie->next_chunk_offset = avio_tell(pb) + 4;
  598.  
  599.     for (i = 0; i < 256; i++)
  600.         ipmovie->palette[i] = 0xFFU << 24;
  601.  
  602.     /* process the first chunk which should be CHUNK_INIT_VIDEO */
  603.     if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_VIDEO)
  604.         return AVERROR_INVALIDDATA;
  605.  
  606.     /* peek ahead to the next chunk-- if it is an init audio chunk, process
  607.      * it; if it is the first video chunk, this is a silent file */
  608.     if (avio_read(pb, chunk_preamble, CHUNK_PREAMBLE_SIZE) !=
  609.         CHUNK_PREAMBLE_SIZE)
  610.         return AVERROR(EIO);
  611.     chunk_type = AV_RL16(&chunk_preamble[2]);
  612.     avio_seek(pb, -CHUNK_PREAMBLE_SIZE, SEEK_CUR);
  613.  
  614.     if (chunk_type == CHUNK_VIDEO)
  615.         ipmovie->audio_type = AV_CODEC_ID_NONE;  /* no audio */
  616.     else if (process_ipmovie_chunk(ipmovie, pb, &pkt) != CHUNK_INIT_AUDIO)
  617.         return AVERROR_INVALIDDATA;
  618.  
  619.     /* initialize the stream decoders */
  620.     st = avformat_new_stream(s, NULL);
  621.     if (!st)
  622.         return AVERROR(ENOMEM);
  623.     avpriv_set_pts_info(st, 63, 1, 1000000);
  624.     ipmovie->video_stream_index = st->index;
  625.     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
  626.     st->codec->codec_id = AV_CODEC_ID_INTERPLAY_VIDEO;
  627.     st->codec->codec_tag = 0;  /* no fourcc */
  628.     st->codec->width = ipmovie->video_width;
  629.     st->codec->height = ipmovie->video_height;
  630.     st->codec->bits_per_coded_sample = ipmovie->video_bpp;
  631.  
  632.     if (ipmovie->audio_type) {
  633.         return init_audio(s);
  634.     } else
  635.        s->ctx_flags |= AVFMTCTX_NOHEADER;
  636.  
  637.     return 0;
  638. }
  639.  
  640. static int ipmovie_read_packet(AVFormatContext *s,
  641.                                AVPacket *pkt)
  642. {
  643.     IPMVEContext *ipmovie = s->priv_data;
  644.     AVIOContext *pb = s->pb;
  645.     int ret;
  646.  
  647.     for (;;) {
  648.     ret = process_ipmovie_chunk(ipmovie, pb, pkt);
  649.     if (ret == CHUNK_BAD)
  650.         ret = AVERROR_INVALIDDATA;
  651.     else if (ret == CHUNK_EOF)
  652.         ret = AVERROR(EIO);
  653.     else if (ret == CHUNK_NOMEM)
  654.         ret = AVERROR(ENOMEM);
  655.     else if (ret == CHUNK_VIDEO)
  656.         ret = 0;
  657.     else if (ret == CHUNK_INIT_VIDEO || ret == CHUNK_INIT_AUDIO)
  658.         continue;
  659.     else
  660.         continue;
  661.  
  662.     return ret;
  663.     }
  664. }
  665.  
  666. AVInputFormat ff_ipmovie_demuxer = {
  667.     .name           = "ipmovie",
  668.     .long_name      = NULL_IF_CONFIG_SMALL("Interplay MVE"),
  669.     .priv_data_size = sizeof(IPMVEContext),
  670.     .read_probe     = ipmovie_probe,
  671.     .read_header    = ipmovie_read_header,
  672.     .read_packet    = ipmovie_read_packet,
  673. };
  674.