libavcodec/vmdav.c - third_party/ffmpeg - Git at Google

 /*
  * Sierra VMD Audio & Video Decoders
  * Copyright (C) 2004 the ffmpeg project
  *
  * 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
  * Sierra VMD audio & video decoders
  * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
  * for more information on the Sierra VMD format, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  *
  * The video decoder outputs PAL8 colorspace data. The decoder expects
  * a 0x330-byte VMD file header to be transmitted via extradata during
  * codec initialization. Each encoded frame that is sent to this decoder
  * is expected to be prepended with the appropriate 16-byte frame
  * information record from the VMD file.
  *
  * The audio decoder, like the video decoder, expects each encoded data
  * chunk to be prepended with the appropriate 16-byte frame information
  * record from the VMD file. It does not require the 0x330-byte VMD file
  * header, but it does need the audio setup parameters passed in through
  * normal libavcodec API means.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #include "libavutil/intreadwrite.h"
 #include "avcodec.h"

 #define VMD_HEADER_SIZE 0x330
 #define PALETTE_COUNT 256

 /*
  * Video Decoder
  */

 typedef struct VmdVideoContext {

     AVCodecContext *avctx;
     AVFrame frame;
     AVFrame prev_frame;

     const unsigned char *buf;
     int size;

     unsigned char palette[PALETTE_COUNT * 4];
     unsigned char *unpack_buffer;
     int unpack_buffer_size;

     int x_off, y_off;
 } VmdVideoContext;

 #define QUEUE_SIZE 0x1000
 #define QUEUE_MASK 0x0FFF

 static void lz_unpack(const unsigned char *src, int src_len,
                       unsigned char *dest, int dest_len)
 {
     const unsigned char *s;
     const unsigned char *s_end;
     unsigned char *d;
     unsigned char *d_end;
     unsigned char queue[QUEUE_SIZE];
     unsigned int qpos;
     unsigned int dataleft;
     unsigned int chainofs;
     unsigned int chainlen;
     unsigned int speclen;
     unsigned char tag;
     unsigned int i, j;

     s = src;
     s_end = src + src_len;
     d = dest;
     d_end = d + dest_len;

     if (s_end - s < 8)
         return;
     dataleft = AV_RL32(s);
     s += 4;
     memset(queue, 0x20, QUEUE_SIZE);
     if (AV_RL32(s) == 0x56781234) {
         s += 4;
         qpos = 0x111;
         speclen = 0xF + 3;
     } else {
         qpos = 0xFEE;
         speclen = 100;  /* no speclen */
     }

     while (s_end - s > 0 && dataleft > 0) {
         tag = *s++;
         if ((tag == 0xFF) && (dataleft > 8)) {
             if (d_end - d < 8 || s_end - s < 8)
                 return;
             for (i = 0; i < 8; i++) {
                 queue[qpos++] = *d++ = *s++;
                 qpos &= QUEUE_MASK;
             }
             dataleft -= 8;
         } else {
             for (i = 0; i < 8; i++) {
                 if (dataleft == 0)
                     break;
                 if (tag & 0x01) {
                     if (d_end - d < 1 || s_end - s < 1)
                         return;
                     queue[qpos++] = *d++ = *s++;
                     qpos &= QUEUE_MASK;
                     dataleft--;
                 } else {
                     if (s_end - s < 2)
                         return;
                     chainofs = *s++;
                     chainofs |= ((*s & 0xF0) << 4);
                     chainlen = (*s++ & 0x0F) + 3;
                     if (chainlen == speclen) {
                         if (s_end - s < 1)
                             return;
                         chainlen = *s++ + 0xF + 3;
                     }
                     if (d_end - d < chainlen)
                         return;
                     for (j = 0; j < chainlen; j++) {
                         *d = queue[chainofs++ & QUEUE_MASK];
                         queue[qpos++] = *d++;
                         qpos &= QUEUE_MASK;
                     }
                     dataleft -= chainlen;
                 }
                 tag >>= 1;
             }
         }
     }
 }

 static int rle_unpack(const unsigned char *src, int src_len, int src_count,
                       unsigned char *dest, int dest_len)
 {
     const unsigned char *ps;
     const unsigned char *ps_end;
     unsigned char *pd;
     int i, l;
     unsigned char *dest_end = dest + dest_len;

     ps = src;
     ps_end = src + src_len;
     pd = dest;
     if (src_count & 1) {
         if (ps_end - ps < 1)
             return 0;
         *pd++ = *ps++;
     }

     src_count >>= 1;
     i = 0;
     do {
         if (ps_end - ps < 1)
             break;
         l = *ps++;
         if (l & 0x80) {
             l = (l & 0x7F) * 2;
             if (dest_end - pd < l || ps_end - ps < l)
                 return ps - src;
             memcpy(pd, ps, l);
             ps += l;
             pd += l;
         } else {
             if (dest_end - pd < i || ps_end - ps < 2)
                 return ps - src;
             for (i = 0; i < l; i++) {
                 *pd++ = ps[0];
                 *pd++ = ps[1];
             }
             ps += 2;
         }
         i += l;
     } while (i < src_count);

     return ps - src;
 }

 static void vmd_decode(VmdVideoContext *s)
 {
     int i;
     unsigned int *palette32;
     unsigned char r, g, b;

     /* point to the start of the encoded data */
     const unsigned char *p = s->buf + 16;
     const unsigned char *p_end = s->buf + s->size;

     const unsigned char *pb;
     const unsigned char *pb_end;
     unsigned char meth;
     unsigned char *dp;   /* pointer to current frame */
     unsigned char *pp;   /* pointer to previous frame */
     unsigned char len;
     int ofs;

     int frame_x, frame_y;
     int frame_width, frame_height;

     frame_x = AV_RL16(&s->buf[6]);
     frame_y = AV_RL16(&s->buf[8]);
     frame_width = AV_RL16(&s->buf[10]) - frame_x + 1;
     frame_height = AV_RL16(&s->buf[12]) - frame_y + 1;
     if (frame_x < 0 || frame_width < 0 ||
         frame_x >= s->avctx->width ||
         frame_width > s->avctx->width ||
         frame_x + frame_width > s->avctx->width)
         return;
     if (frame_y < 0 || frame_height < 0 ||
         frame_y >= s->avctx->height ||
         frame_height > s->avctx->height ||
         frame_y + frame_height > s->avctx->height)
         return;

     if ((frame_width == s->avctx->width && frame_height == s->avctx->height) &&
         (frame_x || frame_y)) {

         s->x_off = frame_x;
         s->y_off = frame_y;
     }
     frame_x -= s->x_off;
     frame_y -= s->y_off;

     /* if only a certain region will be updated, copy the entire previous
      * frame before the decode */
     if (s->prev_frame.data[0] &&
         (frame_x || frame_y || (frame_width != s->avctx->width) ||
         (frame_height != s->avctx->height))) {

         memcpy(s->frame.data[0], s->prev_frame.data[0],
             s->avctx->height * s->frame.linesize[0]);
     }

     /* check if there is a new palette */
     if (s->buf[15] & 0x02) {
         if (p_end - p < 2 + 3 * PALETTE_COUNT)
             return;
         p += 2;
         palette32 = (unsigned int *)s->palette;
         for (i = 0; i < PALETTE_COUNT; i++) {
             r = *p++ * 4;
             g = *p++ * 4;
             b = *p++ * 4;
             palette32[i] = (r << 16) | (g << 8) | (b);
         }
     }
     if (p < p_end) {
         /* originally UnpackFrame in VAG's code */
         pb = p;
         pb_end = p_end;
         meth = *pb++;
         if (meth & 0x80) {
             lz_unpack(pb, p_end - pb, s->unpack_buffer, s->unpack_buffer_size);
             meth &= 0x7F;
             pb = s->unpack_buffer;
             pb_end = s->unpack_buffer + s->unpack_buffer_size;
         }

         dp = &s->frame.data[0][frame_y * s->frame.linesize[0] + frame_x];
         pp = &s->prev_frame.data[0][frame_y * s->prev_frame.linesize[0] + frame_x];
         switch (meth) {
         case 1:
             for (i = 0; i < frame_height; i++) {
                 ofs = 0;
                 do {
                     if (pb_end - pb < 1)
                         return;
                     len = *pb++;
                     if (len & 0x80) {
                         len = (len & 0x7F) + 1;
                         if (ofs + len > frame_width || pb_end - pb < len)
                             return;
                         memcpy(&dp[ofs], pb, len);
                         pb += len;
                         ofs += len;
                     } else {
                         /* interframe pixel copy */
                         if (ofs + len + 1 > frame_width || !s->prev_frame.data[0])
                             return;
                         memcpy(&dp[ofs], &pp[ofs], len + 1);
                         ofs += len + 1;
                     }
                 } while (ofs < frame_width);
                 if (ofs > frame_width) {
                     av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",
                         ofs, frame_width);
                     break;
                 }
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;

         case 2:
             for (i = 0; i < frame_height; i++) {
                 if (pb_end -pb < frame_width)
                     return;
                 memcpy(dp, pb, frame_width);
                 pb += frame_width;
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;

         case 3:
             for (i = 0; i < frame_height; i++) {
                 ofs = 0;
                 do {
                     if (pb_end - pb < 1)
                         return;
                     len = *pb++;
                     if (len & 0x80) {
                         len = (len & 0x7F) + 1;
                         if (pb_end - pb < 1)
                             return;
                         if (*pb++ == 0xFF)
                             len = rle_unpack(pb, pb_end - pb, len, &dp[ofs], frame_width - ofs);
                         else {
                         if (pb_end - pb < len)
                             return;
                             memcpy(&dp[ofs], pb, len);
                         }
                         pb += len;
                         ofs += len;
                     } else {
                         /* interframe pixel copy */
                         if (ofs + len + 1 > frame_width || !s->prev_frame.data[0])
                             return;
                         memcpy(&dp[ofs], &pp[ofs], len + 1);
                         ofs += len + 1;
                     }
                 } while (ofs < frame_width);
                 if (ofs > frame_width) {
                     av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",
                         ofs, frame_width);
                 }
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;
         }
     }
 }

 static av_cold int vmdvideo_decode_init(AVCodecContext *avctx)
 {
     VmdVideoContext *s = avctx->priv_data;
     int i;
     unsigned int *palette32;
     int palette_index = 0;
     unsigned char r, g, b;
     unsigned char *vmd_header;
     unsigned char *raw_palette;

     s->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_PAL8;

     /* make sure the VMD header made it */
     if (s->avctx->extradata_size != VMD_HEADER_SIZE) {
         av_log(s->avctx, AV_LOG_ERROR, "VMD video: expected extradata size of %d\n",
             VMD_HEADER_SIZE);
         return -1;
     }
     vmd_header = (unsigned char *)avctx->extradata;

     s->unpack_buffer_size = AV_RL32(&vmd_header[800]);
     s->unpack_buffer = av_malloc(s->unpack_buffer_size);
     if (!s->unpack_buffer)
         return -1;

     /* load up the initial palette */
     raw_palette = &vmd_header[28];
     palette32 = (unsigned int *)s->palette;
     for (i = 0; i < PALETTE_COUNT; i++) {
         r = raw_palette[palette_index++] * 4;
         g = raw_palette[palette_index++] * 4;
         b = raw_palette[palette_index++] * 4;
         palette32[i] = (r << 16) | (g << 8) | (b);
     }

     avcodec_get_frame_defaults(&s->frame);
     avcodec_get_frame_defaults(&s->prev_frame);

     return 0;
 }

 static int vmdvideo_decode_frame(AVCodecContext *avctx,
                                  void *data, int *data_size,
                                  AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     VmdVideoContext *s = avctx->priv_data;

     s->buf = buf;
     s->size = buf_size;

     if (buf_size < 16)
         return buf_size;

     s->frame.reference = 1;
     if (avctx->get_buffer(avctx, &s->frame)) {
         av_log(s->avctx, AV_LOG_ERROR, "VMD Video: get_buffer() failed\n");
         return -1;
     }

     vmd_decode(s);

     /* make the palette available on the way out */
     memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);

     /* shuffle frames */
     FFSWAP(AVFrame, s->frame, s->prev_frame);
     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->prev_frame;

     /* report that the buffer was completely consumed */
     return buf_size;
 }

 static av_cold int vmdvideo_decode_end(AVCodecContext *avctx)
 {
     VmdVideoContext *s = avctx->priv_data;

     if (s->prev_frame.data[0])
         avctx->release_buffer(avctx, &s->prev_frame);
     av_free(s->unpack_buffer);

     return 0;
 }


 /*
  * Audio Decoder
  */

 #define BLOCK_TYPE_AUDIO    1
 #define BLOCK_TYPE_INITIAL  2
 #define BLOCK_TYPE_SILENCE  3

 typedef struct VmdAudioContext {
     AVCodecContext *avctx;
     int out_bps;
     int predictors[2];
 } VmdAudioContext;

 static const uint16_t vmdaudio_table[128] = {
     0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
     0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
     0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
     0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
     0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
     0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
     0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
     0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
     0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
     0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
     0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
     0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
     0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
 };

 static av_cold int vmdaudio_decode_init(AVCodecContext *avctx)
 {
     VmdAudioContext *s = avctx->priv_data;

     s->avctx = avctx;
     if (avctx->bits_per_coded_sample == 16)
         avctx->sample_fmt = AV_SAMPLE_FMT_S16;
     else
         avctx->sample_fmt = AV_SAMPLE_FMT_U8;
     s->out_bps = av_get_bytes_per_sample(avctx->sample_fmt);

     av_log(avctx, AV_LOG_DEBUG, "%d channels, %d bits/sample, "
            "block align = %d, sample rate = %d\n",
            avctx->channels, avctx->bits_per_coded_sample, avctx->block_align,
            avctx->sample_rate);

     return 0;
 }

 static void vmdaudio_decode_audio(VmdAudioContext *s, unsigned char *data,
     const uint8_t *buf, int buf_size, int stereo)
 {
     int i;
     int chan = 0;
     int16_t *out = (int16_t*)data;

     for(i = 0; i < buf_size; i++) {
         if(buf[i] & 0x80)
             s->predictors[chan] -= vmdaudio_table[buf[i] & 0x7F];
         else
             s->predictors[chan] += vmdaudio_table[buf[i]];
         s->predictors[chan] = av_clip_int16(s->predictors[chan]);
         out[i] = s->predictors[chan];
         chan ^= stereo;
     }
 }

 static int vmdaudio_loadsound(VmdAudioContext *s, unsigned char *data,
     const uint8_t *buf, int silent_chunks, int data_size)
 {
     int silent_size = s->avctx->block_align * silent_chunks * s->out_bps;

     if (silent_chunks) {
         memset(data, s->out_bps == 2 ? 0x00 : 0x80, silent_size);
         data += silent_size;
     }
     if (s->avctx->bits_per_coded_sample == 16)
         vmdaudio_decode_audio(s, data, buf, data_size, s->avctx->channels == 2);
     else {
         /* just copy the data */
         memcpy(data, buf, data_size);
     }

     return silent_size + data_size * s->out_bps;
 }

 static int vmdaudio_decode_frame(AVCodecContext *avctx,
                                  void *data, int *data_size,
                                  AVPacket *avpkt)
 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     VmdAudioContext *s = avctx->priv_data;
     int block_type, silent_chunks;
     unsigned char *output_samples = (unsigned char *)data;

     if (buf_size < 16) {
         av_log(avctx, AV_LOG_WARNING, "skipping small junk packet\n");
         *data_size = 0;
         return buf_size;
     }

     block_type = buf[6];
     if (block_type < BLOCK_TYPE_AUDIO || block_type > BLOCK_TYPE_SILENCE) {
         av_log(avctx, AV_LOG_ERROR, "unknown block type: %d\n", block_type);
         return AVERROR(EINVAL);
     }
     buf      += 16;
     buf_size -= 16;

     silent_chunks = 0;
     if (block_type == BLOCK_TYPE_INITIAL) {
         uint32_t flags;
         if (buf_size < 4)
             return -1;
         flags = AV_RB32(buf);
         silent_chunks  = av_popcount(flags);
         buf      += 4;
         buf_size -= 4;
     } else if (block_type == BLOCK_TYPE_SILENCE) {
         silent_chunks = 1;
         buf_size = 0; // should already be zero but set it just to be sure
     }

     /* ensure output buffer is large enough */
     if (*data_size < (avctx->block_align*silent_chunks + buf_size) * s->out_bps)
         return -1;

     *data_size = vmdaudio_loadsound(s, output_samples, buf, silent_chunks, buf_size);

     return avpkt->size;
 }


 /*
  * Public Data Structures
  */

 AVCodec ff_vmdvideo_decoder = {
     "vmdvideo",
     AVMEDIA_TYPE_VIDEO,
     CODEC_ID_VMDVIDEO,
     sizeof(VmdVideoContext),
     vmdvideo_decode_init,
     NULL,
     vmdvideo_decode_end,
     vmdvideo_decode_frame,
     CODEC_CAP_DR1,
     .long_name = NULL_IF_CONFIG_SMALL("Sierra VMD video"),
 };

 AVCodec ff_vmdaudio_decoder = {
     "vmdaudio",
     AVMEDIA_TYPE_AUDIO,
     CODEC_ID_VMDAUDIO,
     sizeof(VmdAudioContext),
     vmdaudio_decode_init,
     NULL,
     NULL,
     vmdaudio_decode_frame,
     .long_name = NULL_IF_CONFIG_SMALL("Sierra VMD audio"),
 };
	/*
	* Sierra VMD Audio & Video Decoders
	* Copyright (C) 2004 the ffmpeg project
	*
	* 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
	* Sierra VMD audio & video decoders
	* by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
	* for more information on the Sierra VMD format, visit:
	* http://www.pcisys.net/~melanson/codecs/
	*
	* The video decoder outputs PAL8 colorspace data. The decoder expects
	* a 0x330-byte VMD file header to be transmitted via extradata during
	* codec initialization. Each encoded frame that is sent to this decoder
	* is expected to be prepended with the appropriate 16-byte frame
	* information record from the VMD file.
	*
	* The audio decoder, like the video decoder, expects each encoded data
	* chunk to be prepended with the appropriate 16-byte frame information
	* record from the VMD file. It does not require the 0x330-byte VMD file
	* header, but it does need the audio setup parameters passed in through
	* normal libavcodec API means.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#include "libavutil/intreadwrite.h"
	#include "avcodec.h"

	#define VMD_HEADER_SIZE 0x330
	#define PALETTE_COUNT 256

	/*
	* Video Decoder
	*/

	typedef struct VmdVideoContext {

	AVCodecContext *avctx;
	AVFrame frame;
	AVFrame prev_frame;

	const unsigned char *buf;
	int size;

	unsigned char palette[PALETTE_COUNT * 4];
	unsigned char *unpack_buffer;
	int unpack_buffer_size;

	int x_off, y_off;
	} VmdVideoContext;

	#define QUEUE_SIZE 0x1000
	#define QUEUE_MASK 0x0FFF

	static void lz_unpack(const unsigned char *src, int src_len,
	unsigned char *dest, int dest_len)
	{
	const unsigned char *s;
	const unsigned char *s_end;
	unsigned char *d;
	unsigned char *d_end;
	unsigned char queue[QUEUE_SIZE];
	unsigned int qpos;
	unsigned int dataleft;
	unsigned int chainofs;
	unsigned int chainlen;
	unsigned int speclen;
	unsigned char tag;
	unsigned int i, j;

	s = src;
	s_end = src + src_len;
	d = dest;
	d_end = d + dest_len;

	if (s_end - s < 8)
	return;
	dataleft = AV_RL32(s);
	s += 4;
	memset(queue, 0x20, QUEUE_SIZE);
	if (AV_RL32(s) == 0x56781234) {
	s += 4;
	qpos = 0x111;
	speclen = 0xF + 3;
	} else {
	qpos = 0xFEE;
	speclen = 100; /* no speclen */
	}

	while (s_end - s > 0 && dataleft > 0) {
	tag = *s++;
	if ((tag == 0xFF) && (dataleft > 8)) {
	if (d_end - d < 8 \|\| s_end - s < 8)
	return;
	for (i = 0; i < 8; i++) {
	queue[qpos++] = d++ = s++;
	qpos &= QUEUE_MASK;
	}
	dataleft -= 8;
	} else {
	for (i = 0; i < 8; i++) {
	if (dataleft == 0)
	break;
	if (tag & 0x01) {
	if (d_end - d < 1 \|\| s_end - s < 1)
	return;
	queue[qpos++] = d++ = s++;
	qpos &= QUEUE_MASK;
	dataleft--;
	} else {
	if (s_end - s < 2)
	return;
	chainofs = *s++;
	chainofs \|= ((*s & 0xF0) << 4);
	chainlen = (*s++ & 0x0F) + 3;
	if (chainlen == speclen) {
	if (s_end - s < 1)
	return;
	chainlen = *s++ + 0xF + 3;
	}
	if (d_end - d < chainlen)
	return;
	for (j = 0; j < chainlen; j++) {
	*d = queue[chainofs++ & QUEUE_MASK];
	queue[qpos++] = *d++;
	qpos &= QUEUE_MASK;
	}
	dataleft -= chainlen;
	}
	tag >>= 1;
	}
	}
	}
	}

	static int rle_unpack(const unsigned char *src, int src_len, int src_count,
	unsigned char *dest, int dest_len)
	{
	const unsigned char *ps;
	const unsigned char *ps_end;
	unsigned char *pd;
	int i, l;
	unsigned char *dest_end = dest + dest_len;

	ps = src;
	ps_end = src + src_len;
	pd = dest;
	if (src_count & 1) {
	if (ps_end - ps < 1)
	return 0;
	pd++ = ps++;
	}

	src_count >>= 1;
	i = 0;
	do {
	if (ps_end - ps < 1)
	break;
	l = *ps++;
	if (l & 0x80) {
	l = (l & 0x7F) * 2;
	if (dest_end - pd < l \|\| ps_end - ps < l)
	return ps - src;
	memcpy(pd, ps, l);
	ps += l;
	pd += l;
	} else {
	if (dest_end - pd < i \|\| ps_end - ps < 2)
	return ps - src;
	for (i = 0; i < l; i++) {
	*pd++ = ps[0];
	*pd++ = ps[1];
	}
	ps += 2;
	}
	i += l;
	} while (i < src_count);

	return ps - src;
	}

	static void vmd_decode(VmdVideoContext *s)
	{
	int i;
	unsigned int *palette32;
	unsigned char r, g, b;

	/* point to the start of the encoded data */
	const unsigned char *p = s->buf + 16;
	const unsigned char *p_end = s->buf + s->size;

	const unsigned char *pb;
	const unsigned char *pb_end;
	unsigned char meth;
	unsigned char dp; / pointer to current frame */
	unsigned char pp; / pointer to previous frame */
	unsigned char len;
	int ofs;

	int frame_x, frame_y;
	int frame_width, frame_height;

	frame_x = AV_RL16(&s->buf[6]);
	frame_y = AV_RL16(&s->buf[8]);
	frame_width = AV_RL16(&s->buf[10]) - frame_x + 1;
	frame_height = AV_RL16(&s->buf[12]) - frame_y + 1;
	if (frame_x < 0 \|\| frame_width < 0 \|\|
	frame_x >= s->avctx->width \|\|
	frame_width > s->avctx->width \|\|
	frame_x + frame_width > s->avctx->width)
	return;
	if (frame_y < 0 \|\| frame_height < 0 \|\|
	frame_y >= s->avctx->height \|\|
	frame_height > s->avctx->height \|\|
	frame_y + frame_height > s->avctx->height)
	return;

	if ((frame_width == s->avctx->width && frame_height == s->avctx->height) &&
	(frame_x \|\| frame_y)) {

	s->x_off = frame_x;
	s->y_off = frame_y;
	}
	frame_x -= s->x_off;
	frame_y -= s->y_off;

	/* if only a certain region will be updated, copy the entire previous
	* frame before the decode */
	if (s->prev_frame.data[0] &&
	(frame_x \|\| frame_y \|\| (frame_width != s->avctx->width) \|\|
	(frame_height != s->avctx->height))) {

	memcpy(s->frame.data[0], s->prev_frame.data[0],
	s->avctx->height * s->frame.linesize[0]);
	}

	/* check if there is a new palette */
	if (s->buf[15] & 0x02) {
	if (p_end - p < 2 + 3 * PALETTE_COUNT)
	return;
	p += 2;
	palette32 = (unsigned int *)s->palette;
	for (i = 0; i < PALETTE_COUNT; i++) {
	r = p++ 4;
	g = p++ 4;
	b = p++ 4;
	palette32[i] = (r << 16) \| (g << 8) \| (b);
	}
	}
	if (p < p_end) {
	/* originally UnpackFrame in VAG's code */
	pb = p;
	pb_end = p_end;
	meth = *pb++;
	if (meth & 0x80) {
	lz_unpack(pb, p_end - pb, s->unpack_buffer, s->unpack_buffer_size);
	meth &= 0x7F;
	pb = s->unpack_buffer;
	pb_end = s->unpack_buffer + s->unpack_buffer_size;
	}

	dp = &s->frame.data[0][frame_y * s->frame.linesize[0] + frame_x];
	pp = &s->prev_frame.data[0][frame_y * s->prev_frame.linesize[0] + frame_x];
	switch (meth) {
	case 1:
	for (i = 0; i < frame_height; i++) {
	ofs = 0;
	do {
	if (pb_end - pb < 1)
	return;
	len = *pb++;
	if (len & 0x80) {
	len = (len & 0x7F) + 1;
	if (ofs + len > frame_width \|\| pb_end - pb < len)
	return;
	memcpy(&dp[ofs], pb, len);
	pb += len;
	ofs += len;
	} else {
	/* interframe pixel copy */
	if (ofs + len + 1 > frame_width \|\| !s->prev_frame.data[0])
	return;
	memcpy(&dp[ofs], &pp[ofs], len + 1);
	ofs += len + 1;
	}
	} while (ofs < frame_width);
	if (ofs > frame_width) {
	av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",
	ofs, frame_width);
	break;
	}
	dp += s->frame.linesize[0];
	pp += s->prev_frame.linesize[0];
	}
	break;

	case 2:
	for (i = 0; i < frame_height; i++) {
	if (pb_end -pb < frame_width)
	return;
	memcpy(dp, pb, frame_width);
	pb += frame_width;
	dp += s->frame.linesize[0];
	pp += s->prev_frame.linesize[0];
	}
	break;

	case 3:
	for (i = 0; i < frame_height; i++) {
	ofs = 0;
	do {
	if (pb_end - pb < 1)
	return;
	len = *pb++;
	if (len & 0x80) {
	len = (len & 0x7F) + 1;
	if (pb_end - pb < 1)
	return;
	if (*pb++ == 0xFF)
	len = rle_unpack(pb, pb_end - pb, len, &dp[ofs], frame_width - ofs);
	else {
	if (pb_end - pb < len)
	return;
	memcpy(&dp[ofs], pb, len);
	}
	pb += len;
	ofs += len;
	} else {
	/* interframe pixel copy */
	if (ofs + len + 1 > frame_width \|\| !s->prev_frame.data[0])
	return;
	memcpy(&dp[ofs], &pp[ofs], len + 1);
	ofs += len + 1;
	}
	} while (ofs < frame_width);
	if (ofs > frame_width) {
	av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",
	ofs, frame_width);
	}
	dp += s->frame.linesize[0];
	pp += s->prev_frame.linesize[0];
	}
	break;
	}
	}
	}

	static av_cold int vmdvideo_decode_init(AVCodecContext *avctx)
	{
	VmdVideoContext *s = avctx->priv_data;
	int i;
	unsigned int *palette32;
	int palette_index = 0;
	unsigned char r, g, b;
	unsigned char *vmd_header;
	unsigned char *raw_palette;

	s->avctx = avctx;
	avctx->pix_fmt = PIX_FMT_PAL8;

	/* make sure the VMD header made it */
	if (s->avctx->extradata_size != VMD_HEADER_SIZE) {
	av_log(s->avctx, AV_LOG_ERROR, "VMD video: expected extradata size of %d\n",
	VMD_HEADER_SIZE);
	return -1;
	}
	vmd_header = (unsigned char *)avctx->extradata;

	s->unpack_buffer_size = AV_RL32(&vmd_header[800]);
	s->unpack_buffer = av_malloc(s->unpack_buffer_size);
	if (!s->unpack_buffer)
	return -1;

	/* load up the initial palette */
	raw_palette = &vmd_header[28];
	palette32 = (unsigned int *)s->palette;
	for (i = 0; i < PALETTE_COUNT; i++) {
	r = raw_palette[palette_index++] * 4;
	g = raw_palette[palette_index++] * 4;
	b = raw_palette[palette_index++] * 4;
	palette32[i] = (r << 16) \| (g << 8) \| (b);
	}

	avcodec_get_frame_defaults(&s->frame);
	avcodec_get_frame_defaults(&s->prev_frame);

	return 0;
	}

	static int vmdvideo_decode_frame(AVCodecContext *avctx,
	void data, int data_size,
	AVPacket *avpkt)
	{
	const uint8_t *buf = avpkt->data;
	int buf_size = avpkt->size;
	VmdVideoContext *s = avctx->priv_data;

	s->buf = buf;
	s->size = buf_size;

	if (buf_size < 16)
	return buf_size;

	s->frame.reference = 1;
	if (avctx->get_buffer(avctx, &s->frame)) {
	av_log(s->avctx, AV_LOG_ERROR, "VMD Video: get_buffer() failed\n");
	return -1;
	}

	vmd_decode(s);

	/* make the palette available on the way out */
	memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);

	/* shuffle frames */
	FFSWAP(AVFrame, s->frame, s->prev_frame);
	if (s->frame.data[0])
	avctx->release_buffer(avctx, &s->frame);

	*data_size = sizeof(AVFrame);
	(AVFrame)data = s->prev_frame;

	/* report that the buffer was completely consumed */
	return buf_size;
	}

	static av_cold int vmdvideo_decode_end(AVCodecContext *avctx)
	{
	VmdVideoContext *s = avctx->priv_data;

	if (s->prev_frame.data[0])
	avctx->release_buffer(avctx, &s->prev_frame);
	av_free(s->unpack_buffer);

	return 0;
	}


	/*
	* Audio Decoder
	*/

	#define BLOCK_TYPE_AUDIO 1
	#define BLOCK_TYPE_INITIAL 2
	#define BLOCK_TYPE_SILENCE 3

	typedef struct VmdAudioContext {
	AVCodecContext *avctx;
	int out_bps;
	int predictors[2];
	} VmdAudioContext;

	static const uint16_t vmdaudio_table[128] = {
	0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
	0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
	0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
	0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
	0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
	0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
	0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
	0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
	0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
	0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
	0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
	0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
	0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
	};

	static av_cold int vmdaudio_decode_init(AVCodecContext *avctx)
	{
	VmdAudioContext *s = avctx->priv_data;

	s->avctx = avctx;
	if (avctx->bits_per_coded_sample == 16)
	avctx->sample_fmt = AV_SAMPLE_FMT_S16;
	else
	avctx->sample_fmt = AV_SAMPLE_FMT_U8;
	s->out_bps = av_get_bytes_per_sample(avctx->sample_fmt);

	av_log(avctx, AV_LOG_DEBUG, "%d channels, %d bits/sample, "
	"block align = %d, sample rate = %d\n",
	avctx->channels, avctx->bits_per_coded_sample, avctx->block_align,
	avctx->sample_rate);

	return 0;
	}

	static void vmdaudio_decode_audio(VmdAudioContext s, unsigned char data,
	const uint8_t *buf, int buf_size, int stereo)
	{
	int i;
	int chan = 0;
	int16_t out = (int16_t)data;

	for(i = 0; i < buf_size; i++) {
	if(buf[i] & 0x80)
	s->predictors[chan] -= vmdaudio_table[buf[i] & 0x7F];
	else
	s->predictors[chan] += vmdaudio_table[buf[i]];
	s->predictors[chan] = av_clip_int16(s->predictors[chan]);
	out[i] = s->predictors[chan];
	chan ^= stereo;
	}
	}

	static int vmdaudio_loadsound(VmdAudioContext s, unsigned char data,
	const uint8_t *buf, int silent_chunks, int data_size)
	{
	int silent_size = s->avctx->block_align * silent_chunks * s->out_bps;

	if (silent_chunks) {
	memset(data, s->out_bps == 2 ? 0x00 : 0x80, silent_size);
	data += silent_size;
	}
	if (s->avctx->bits_per_coded_sample == 16)
	vmdaudio_decode_audio(s, data, buf, data_size, s->avctx->channels == 2);
	else {
	/* just copy the data */
	memcpy(data, buf, data_size);
	}

	return silent_size + data_size * s->out_bps;
	}

	static int vmdaudio_decode_frame(AVCodecContext *avctx,
	void data, int data_size,
	AVPacket *avpkt)
	{
	const uint8_t *buf = avpkt->data;
	int buf_size = avpkt->size;
	VmdAudioContext *s = avctx->priv_data;
	int block_type, silent_chunks;
	unsigned char output_samples = (unsigned char )data;

	if (buf_size < 16) {
	av_log(avctx, AV_LOG_WARNING, "skipping small junk packet\n");
	*data_size = 0;
	return buf_size;
	}

	block_type = buf[6];
	if (block_type < BLOCK_TYPE_AUDIO \|\| block_type > BLOCK_TYPE_SILENCE) {
	av_log(avctx, AV_LOG_ERROR, "unknown block type: %d\n", block_type);
	return AVERROR(EINVAL);
	}
	buf += 16;
	buf_size -= 16;

	silent_chunks = 0;
	if (block_type == BLOCK_TYPE_INITIAL) {
	uint32_t flags;
	if (buf_size < 4)
	return -1;
	flags = AV_RB32(buf);
	silent_chunks = av_popcount(flags);
	buf += 4;
	buf_size -= 4;
	} else if (block_type == BLOCK_TYPE_SILENCE) {
	silent_chunks = 1;
	buf_size = 0; // should already be zero but set it just to be sure
	}

	/* ensure output buffer is large enough */
	if (data_size < (avctx->block_alignsilent_chunks + buf_size) * s->out_bps)
	return -1;

	*data_size = vmdaudio_loadsound(s, output_samples, buf, silent_chunks, buf_size);

	return avpkt->size;
	}


	/*
	* Public Data Structures
	*/

	AVCodec ff_vmdvideo_decoder = {
	"vmdvideo",
	AVMEDIA_TYPE_VIDEO,
	CODEC_ID_VMDVIDEO,
	sizeof(VmdVideoContext),
	vmdvideo_decode_init,
	NULL,
	vmdvideo_decode_end,
	vmdvideo_decode_frame,
	CODEC_CAP_DR1,
	.long_name = NULL_IF_CONFIG_SMALL("Sierra VMD video"),
	};

	AVCodec ff_vmdaudio_decoder = {
	"vmdaudio",
	AVMEDIA_TYPE_AUDIO,
	CODEC_ID_VMDAUDIO,
	sizeof(VmdAudioContext),
	vmdaudio_decode_init,
	NULL,
	NULL,
	vmdaudio_decode_frame,
	.long_name = NULL_IF_CONFIG_SMALL("Sierra VMD audio"),
	};