yading@10: /*
yading@10:  * Sierra VMD Audio & Video Decoders
yading@10:  * Copyright (C) 2004 the ffmpeg project
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 Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Sierra VMD audio & video decoders
yading@10:  * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)
yading@10:  * for more information on the Sierra VMD format, visit:
yading@10:  *   http://www.pcisys.net/~melanson/codecs/
yading@10:  *
yading@10:  * The video decoder outputs PAL8 colorspace data. The decoder expects
yading@10:  * a 0x330-byte VMD file header to be transmitted via extradata during
yading@10:  * codec initialization. Each encoded frame that is sent to this decoder
yading@10:  * is expected to be prepended with the appropriate 16-byte frame
yading@10:  * information record from the VMD file.
yading@10:  *
yading@10:  * The audio decoder, like the video decoder, expects each encoded data
yading@10:  * chunk to be prepended with the appropriate 16-byte frame information
yading@10:  * record from the VMD file. It does not require the 0x330-byte VMD file
yading@10:  * header, but it does need the audio setup parameters passed in through
yading@10:  * normal libavcodec API means.
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: 
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/common.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "bytestream.h"
yading@10: 
yading@10: #define VMD_HEADER_SIZE 0x330
yading@10: #define PALETTE_COUNT 256
yading@10: 
yading@10: /*
yading@10:  * Video Decoder
yading@10:  */
yading@10: 
yading@10: typedef struct VmdVideoContext {
yading@10: 
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame prev_frame;
yading@10: 
yading@10:     const unsigned char *buf;
yading@10:     int size;
yading@10: 
yading@10:     unsigned char palette[PALETTE_COUNT * 4];
yading@10:     unsigned char *unpack_buffer;
yading@10:     int unpack_buffer_size;
yading@10: 
yading@10:     int x_off, y_off;
yading@10: } VmdVideoContext;
yading@10: 
yading@10: #define QUEUE_SIZE 0x1000
yading@10: #define QUEUE_MASK 0x0FFF
yading@10: 
yading@10: static void lz_unpack(const unsigned char *src, int src_len,
yading@10:                       unsigned char *dest, int dest_len)
yading@10: {
yading@10:     unsigned char *d;
yading@10:     unsigned char *d_end;
yading@10:     unsigned char queue[QUEUE_SIZE];
yading@10:     unsigned int qpos;
yading@10:     unsigned int dataleft;
yading@10:     unsigned int chainofs;
yading@10:     unsigned int chainlen;
yading@10:     unsigned int speclen;
yading@10:     unsigned char tag;
yading@10:     unsigned int i, j;
yading@10:     GetByteContext gb;
yading@10: 
yading@10:     bytestream2_init(&gb, src, src_len);
yading@10:     d = dest;
yading@10:     d_end = d + dest_len;
yading@10:     dataleft = bytestream2_get_le32(&gb);
yading@10:     memset(queue, 0x20, QUEUE_SIZE);
yading@10:     if (bytestream2_get_bytes_left(&gb) < 4)
yading@10:         return;
yading@10:     if (bytestream2_peek_le32(&gb) == 0x56781234) {
yading@10:         bytestream2_skipu(&gb, 4);
yading@10:         qpos = 0x111;
yading@10:         speclen = 0xF + 3;
yading@10:     } else {
yading@10:         qpos = 0xFEE;
yading@10:         speclen = 100;  /* no speclen */
yading@10:     }
yading@10: 
yading@10:     while (dataleft > 0 && bytestream2_get_bytes_left(&gb) > 0) {
yading@10:         tag = bytestream2_get_byteu(&gb);
yading@10:         if ((tag == 0xFF) && (dataleft > 8)) {
yading@10:             if (d_end - d < 8 || bytestream2_get_bytes_left(&gb) < 8)
yading@10:                 return;
yading@10:             for (i = 0; i < 8; i++) {
yading@10:                 queue[qpos++] = *d++ = bytestream2_get_byteu(&gb);
yading@10:                 qpos &= QUEUE_MASK;
yading@10:             }
yading@10:             dataleft -= 8;
yading@10:         } else {
yading@10:             for (i = 0; i < 8; i++) {
yading@10:                 if (dataleft == 0)
yading@10:                     break;
yading@10:                 if (tag & 0x01) {
yading@10:                     if (d_end - d < 1 || bytestream2_get_bytes_left(&gb) < 1)
yading@10:                         return;
yading@10:                     queue[qpos++] = *d++ = bytestream2_get_byteu(&gb);
yading@10:                     qpos &= QUEUE_MASK;
yading@10:                     dataleft--;
yading@10:                 } else {
yading@10:                     chainofs = bytestream2_get_byte(&gb);
yading@10:                     chainofs |= ((bytestream2_peek_byte(&gb) & 0xF0) << 4);
yading@10:                     chainlen = (bytestream2_get_byte(&gb) & 0x0F) + 3;
yading@10:                     if (chainlen == speclen) {
yading@10:                         chainlen = bytestream2_get_byte(&gb) + 0xF + 3;
yading@10:                     }
yading@10:                     if (d_end - d < chainlen)
yading@10:                         return;
yading@10:                     for (j = 0; j < chainlen; j++) {
yading@10:                         *d = queue[chainofs++ & QUEUE_MASK];
yading@10:                         queue[qpos++] = *d++;
yading@10:                         qpos &= QUEUE_MASK;
yading@10:                     }
yading@10:                     dataleft -= chainlen;
yading@10:                 }
yading@10:                 tag >>= 1;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: }
yading@10: static int rle_unpack(const unsigned char *src, unsigned char *dest,
yading@10:                       int src_count, int src_size, int dest_len)
yading@10: {
yading@10:     unsigned char *pd;
yading@10:     int i, l;
yading@10:     unsigned char *dest_end = dest + dest_len;
yading@10:     GetByteContext gb;
yading@10: 
yading@10:     bytestream2_init(&gb, src, src_size);
yading@10:     pd = dest;
yading@10:     if (src_count & 1) {
yading@10:         if (bytestream2_get_bytes_left(&gb) < 1)
yading@10:             return 0;
yading@10:         *pd++ = bytestream2_get_byteu(&gb);
yading@10:     }
yading@10: 
yading@10:     src_count >>= 1;
yading@10:     i = 0;
yading@10:     do {
yading@10:         if (bytestream2_get_bytes_left(&gb) < 1)
yading@10:             break;
yading@10:         l = bytestream2_get_byteu(&gb);
yading@10:         if (l & 0x80) {
yading@10:             l = (l & 0x7F) * 2;
yading@10:             if (dest_end - pd < l || bytestream2_get_bytes_left(&gb) < l)
yading@10:                 return bytestream2_tell(&gb);
yading@10:             bytestream2_get_bufferu(&gb, pd, l);
yading@10:             pd += l;
yading@10:         } else {
yading@10:             if (dest_end - pd < i || bytestream2_get_bytes_left(&gb) < 2)
yading@10:                 return bytestream2_tell(&gb);
yading@10:             for (i = 0; i < l; i++) {
yading@10:                 *pd++ = bytestream2_get_byteu(&gb);
yading@10:                 *pd++ = bytestream2_get_byteu(&gb);
yading@10:             }
yading@10:             bytestream2_skip(&gb, 2);
yading@10:         }
yading@10:         i += l;
yading@10:     } while (i < src_count);
yading@10: 
yading@10:     return bytestream2_tell(&gb);
yading@10: }
yading@10: 
yading@10: static void vmd_decode(VmdVideoContext *s, AVFrame *frame)
yading@10: {
yading@10:     int i;
yading@10:     unsigned int *palette32;
yading@10:     unsigned char r, g, b;
yading@10: 
yading@10:     GetByteContext gb;
yading@10: 
yading@10:     unsigned char meth;
yading@10:     unsigned char *dp;   /* pointer to current frame */
yading@10:     unsigned char *pp;   /* pointer to previous frame */
yading@10:     unsigned char len;
yading@10:     int ofs;
yading@10: 
yading@10:     int frame_x, frame_y;
yading@10:     int frame_width, frame_height;
yading@10: 
yading@10:     frame_x = AV_RL16(&s->buf[6]);
yading@10:     frame_y = AV_RL16(&s->buf[8]);
yading@10:     frame_width = AV_RL16(&s->buf[10]) - frame_x + 1;
yading@10:     frame_height = AV_RL16(&s->buf[12]) - frame_y + 1;
yading@10:     if (frame_x < 0 || frame_width < 0 ||
yading@10:         frame_x >= s->avctx->width ||
yading@10:         frame_width > s->avctx->width ||
yading@10:         frame_x + frame_width > s->avctx->width)
yading@10:         return;
yading@10:     if (frame_y < 0 || frame_height < 0 ||
yading@10:         frame_y >= s->avctx->height ||
yading@10:         frame_height > s->avctx->height ||
yading@10:         frame_y + frame_height > s->avctx->height)
yading@10:         return;
yading@10: 
yading@10:     if ((frame_width == s->avctx->width && frame_height == s->avctx->height) &&
yading@10:         (frame_x || frame_y)) {
yading@10: 
yading@10:         s->x_off = frame_x;
yading@10:         s->y_off = frame_y;
yading@10:     }
yading@10:     frame_x -= s->x_off;
yading@10:     frame_y -= s->y_off;
yading@10: 
yading@10:     /* if only a certain region will be updated, copy the entire previous
yading@10:      * frame before the decode */
yading@10:     if (s->prev_frame.data[0] &&
yading@10:         (frame_x || frame_y || (frame_width != s->avctx->width) ||
yading@10:         (frame_height != s->avctx->height))) {
yading@10: 
yading@10:         memcpy(frame->data[0], s->prev_frame.data[0],
yading@10:             s->avctx->height * frame->linesize[0]);
yading@10:     }
yading@10: 
yading@10:     /* check if there is a new palette */
yading@10:     bytestream2_init(&gb, s->buf + 16, s->size - 16);
yading@10:     if (s->buf[15] & 0x02) {
yading@10:         bytestream2_skip(&gb, 2);
yading@10:         palette32 = (unsigned int *)s->palette;
yading@10:         if (bytestream2_get_bytes_left(&gb) >= PALETTE_COUNT * 3) {
yading@10:             for (i = 0; i < PALETTE_COUNT; i++) {
yading@10:                 r = bytestream2_get_byteu(&gb) * 4;
yading@10:                 g = bytestream2_get_byteu(&gb) * 4;
yading@10:                 b = bytestream2_get_byteu(&gb) * 4;
yading@10:                 palette32[i] = 0xFFU << 24 | (r << 16) | (g << 8) | (b);
yading@10:                 palette32[i] |= palette32[i] >> 6 & 0x30303;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     if (s->size > 0) {
yading@10:         /* originally UnpackFrame in VAG's code */
yading@10:         bytestream2_init(&gb, gb.buffer, s->buf + s->size - gb.buffer);
yading@10:         if (bytestream2_get_bytes_left(&gb) < 1)
yading@10:             return;
yading@10:         meth = bytestream2_get_byteu(&gb);
yading@10:         if (meth & 0x80) {
yading@10:             lz_unpack(gb.buffer, bytestream2_get_bytes_left(&gb),
yading@10:                       s->unpack_buffer, s->unpack_buffer_size);
yading@10:             meth &= 0x7F;
yading@10:             bytestream2_init(&gb, s->unpack_buffer, s->unpack_buffer_size);
yading@10:         }
yading@10: 
yading@10:         dp = &frame->data[0][frame_y * frame->linesize[0] + frame_x];
yading@10:         pp = &s->prev_frame.data[0][frame_y * s->prev_frame.linesize[0] + frame_x];
yading@10:         switch (meth) {
yading@10:         case 1:
yading@10:             for (i = 0; i < frame_height; i++) {
yading@10:                 ofs = 0;
yading@10:                 do {
yading@10:                     len = bytestream2_get_byte(&gb);
yading@10:                     if (len & 0x80) {
yading@10:                         len = (len & 0x7F) + 1;
yading@10:                         if (ofs + len > frame_width || bytestream2_get_bytes_left(&gb) < len)
yading@10:                             return;
yading@10:                         bytestream2_get_bufferu(&gb, &dp[ofs], len);
yading@10:                         ofs += len;
yading@10:                     } else {
yading@10:                         /* interframe pixel copy */
yading@10:                         if (ofs + len + 1 > frame_width || !s->prev_frame.data[0])
yading@10:                             return;
yading@10:                         memcpy(&dp[ofs], &pp[ofs], len + 1);
yading@10:                         ofs += len + 1;
yading@10:                     }
yading@10:                 } while (ofs < frame_width);
yading@10:                 if (ofs > frame_width) {
yading@10:                     av_log(s->avctx, AV_LOG_ERROR, "offset > width (%d > %d)\n",
yading@10:                         ofs, frame_width);
yading@10:                     break;
yading@10:                 }
yading@10:                 dp += frame->linesize[0];
yading@10:                 pp += s->prev_frame.linesize[0];
yading@10:             }
yading@10:             break;
yading@10: 
yading@10:         case 2:
yading@10:             for (i = 0; i < frame_height; i++) {
yading@10:                 bytestream2_get_buffer(&gb, dp, frame_width);
yading@10:                 dp += frame->linesize[0];
yading@10:                 pp += s->prev_frame.linesize[0];
yading@10:             }
yading@10:             break;
yading@10: 
yading@10:         case 3:
yading@10:             for (i = 0; i < frame_height; i++) {
yading@10:                 ofs = 0;
yading@10:                 do {
yading@10:                     len = bytestream2_get_byte(&gb);
yading@10:                     if (len & 0x80) {
yading@10:                         len = (len & 0x7F) + 1;
yading@10:                         if (bytestream2_get_byte(&gb) == 0xFF)
yading@10:                             len = rle_unpack(gb.buffer, &dp[ofs],
yading@10:                                              len, bytestream2_get_bytes_left(&gb),
yading@10:                                              frame_width - ofs);
yading@10:                         else
yading@10:                             bytestream2_get_buffer(&gb, &dp[ofs], len);
yading@10:                         bytestream2_skip(&gb, len);
yading@10:                     } else {
yading@10:                         /* interframe pixel copy */
yading@10:                         if (ofs + len + 1 > frame_width || !s->prev_frame.data[0])
yading@10:                             return;
yading@10:                         memcpy(&dp[ofs], &pp[ofs], len + 1);
yading@10:                         ofs += len + 1;
yading@10:                     }
yading@10:                 } while (ofs < frame_width);
yading@10:                 if (ofs > frame_width) {
yading@10:                     av_log(s->avctx, AV_LOG_ERROR, "offset > width (%d > %d)\n",
yading@10:                         ofs, frame_width);
yading@10:                 }
yading@10:                 dp += frame->linesize[0];
yading@10:                 pp += s->prev_frame.linesize[0];
yading@10:             }
yading@10:             break;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static av_cold int vmdvideo_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     VmdVideoContext *s = avctx->priv_data;
yading@10:     int i;
yading@10:     unsigned int *palette32;
yading@10:     int palette_index = 0;
yading@10:     unsigned char r, g, b;
yading@10:     unsigned char *vmd_header;
yading@10:     unsigned char *raw_palette;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     /* make sure the VMD header made it */
yading@10:     if (s->avctx->extradata_size != VMD_HEADER_SIZE) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "expected extradata size of %d\n",
yading@10:             VMD_HEADER_SIZE);
yading@10:         return -1;
yading@10:     }
yading@10:     vmd_header = (unsigned char *)avctx->extradata;
yading@10: 
yading@10:     s->unpack_buffer_size = AV_RL32(&vmd_header[800]);
yading@10:     s->unpack_buffer = av_malloc(s->unpack_buffer_size);
yading@10:     if (!s->unpack_buffer)
yading@10:         return -1;
yading@10: 
yading@10:     /* load up the initial palette */
yading@10:     raw_palette = &vmd_header[28];
yading@10:     palette32 = (unsigned int *)s->palette;
yading@10:     for (i = 0; i < PALETTE_COUNT; i++) {
yading@10:         r = raw_palette[palette_index++] * 4;
yading@10:         g = raw_palette[palette_index++] * 4;
yading@10:         b = raw_palette[palette_index++] * 4;
yading@10:         palette32[i] = (r << 16) | (g << 8) | (b);
yading@10:     }
yading@10: 
yading@10:     avcodec_get_frame_defaults(&s->prev_frame);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int vmdvideo_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:     VmdVideoContext *s = avctx->priv_data;
yading@10:     AVFrame *frame = data;
yading@10:     int ret;
yading@10: 
yading@10:     s->buf = buf;
yading@10:     s->size = buf_size;
yading@10: 
yading@10:     if (buf_size < 16)
yading@10:         return buf_size;
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:     vmd_decode(s, frame);
yading@10: 
yading@10:     /* make the palette available on the way out */
yading@10:     memcpy(frame->data[1], s->palette, PALETTE_COUNT * 4);
yading@10: 
yading@10:     /* shuffle frames */
yading@10:     av_frame_unref(&s->prev_frame);
yading@10:     if ((ret = av_frame_ref(&s->prev_frame, frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame      = 1;
yading@10: 
yading@10:     /* report that the buffer was completely consumed */
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int vmdvideo_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     VmdVideoContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_unref(&s->prev_frame);
yading@10:     av_free(s->unpack_buffer);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: /*
yading@10:  * Audio Decoder
yading@10:  */
yading@10: 
yading@10: #define BLOCK_TYPE_AUDIO    1
yading@10: #define BLOCK_TYPE_INITIAL  2
yading@10: #define BLOCK_TYPE_SILENCE  3
yading@10: 
yading@10: typedef struct VmdAudioContext {
yading@10:     int out_bps;
yading@10:     int chunk_size;
yading@10: } VmdAudioContext;
yading@10: 
yading@10: static const uint16_t vmdaudio_table[128] = {
yading@10:     0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
yading@10:     0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
yading@10:     0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
yading@10:     0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
yading@10:     0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
yading@10:     0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
yading@10:     0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
yading@10:     0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
yading@10:     0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
yading@10:     0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
yading@10:     0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
yading@10:     0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
yading@10:     0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
yading@10: };
yading@10: 
yading@10: static av_cold int vmdaudio_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     VmdAudioContext *s = avctx->priv_data;
yading@10: 
yading@10:     if (avctx->channels < 1 || avctx->channels > 2) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10:     if (avctx->block_align < 1 || avctx->block_align % avctx->channels) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "invalid block align\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO :
yading@10:                                                    AV_CH_LAYOUT_STEREO;
yading@10: 
yading@10:     if (avctx->bits_per_coded_sample == 16)
yading@10:         avctx->sample_fmt = AV_SAMPLE_FMT_S16;
yading@10:     else
yading@10:         avctx->sample_fmt = AV_SAMPLE_FMT_U8;
yading@10:     s->out_bps = av_get_bytes_per_sample(avctx->sample_fmt);
yading@10: 
yading@10:     s->chunk_size = avctx->block_align + avctx->channels * (s->out_bps == 2);
yading@10: 
yading@10:     av_log(avctx, AV_LOG_DEBUG, "%d channels, %d bits/sample, "
yading@10:            "block align = %d, sample rate = %d\n",
yading@10:            avctx->channels, avctx->bits_per_coded_sample, avctx->block_align,
yading@10:            avctx->sample_rate);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static void decode_audio_s16(int16_t *out, const uint8_t *buf, int buf_size,
yading@10:                              int channels)
yading@10: {
yading@10:     int ch;
yading@10:     const uint8_t *buf_end = buf + buf_size;
yading@10:     int predictor[2];
yading@10:     int st = channels - 1;
yading@10: 
yading@10:     /* decode initial raw sample */
yading@10:     for (ch = 0; ch < channels; ch++) {
yading@10:         predictor[ch] = (int16_t)AV_RL16(buf);
yading@10:         buf += 2;
yading@10:         *out++ = predictor[ch];
yading@10:     }
yading@10: 
yading@10:     /* decode DPCM samples */
yading@10:     ch = 0;
yading@10:     while (buf < buf_end) {
yading@10:         uint8_t b = *buf++;
yading@10:         if (b & 0x80)
yading@10:             predictor[ch] -= vmdaudio_table[b & 0x7F];
yading@10:         else
yading@10:             predictor[ch] += vmdaudio_table[b];
yading@10:         predictor[ch] = av_clip_int16(predictor[ch]);
yading@10:         *out++ = predictor[ch];
yading@10:         ch ^= st;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
yading@10:                                  int *got_frame_ptr, AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame     = data;
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     const uint8_t *buf_end;
yading@10:     int buf_size = avpkt->size;
yading@10:     VmdAudioContext *s = avctx->priv_data;
yading@10:     int block_type, silent_chunks, audio_chunks;
yading@10:     int ret;
yading@10:     uint8_t *output_samples_u8;
yading@10:     int16_t *output_samples_s16;
yading@10: 
yading@10:     if (buf_size < 16) {
yading@10:         av_log(avctx, AV_LOG_WARNING, "skipping small junk packet\n");
yading@10:         *got_frame_ptr = 0;
yading@10:         return buf_size;
yading@10:     }
yading@10: 
yading@10:     block_type = buf[6];
yading@10:     if (block_type < BLOCK_TYPE_AUDIO || block_type > BLOCK_TYPE_SILENCE) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "unknown block type: %d\n", block_type);
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10:     buf      += 16;
yading@10:     buf_size -= 16;
yading@10: 
yading@10:     /* get number of silent chunks */
yading@10:     silent_chunks = 0;
yading@10:     if (block_type == BLOCK_TYPE_INITIAL) {
yading@10:         uint32_t flags;
yading@10:         if (buf_size < 4) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
yading@10:             return AVERROR(EINVAL);
yading@10:         }
yading@10:         flags         = AV_RB32(buf);
yading@10:         silent_chunks = av_popcount(flags);
yading@10:         buf      += 4;
yading@10:         buf_size -= 4;
yading@10:     } else if (block_type == BLOCK_TYPE_SILENCE) {
yading@10:         silent_chunks = 1;
yading@10:         buf_size = 0; // should already be zero but set it just to be sure
yading@10:     }
yading@10: 
yading@10:     /* ensure output buffer is large enough */
yading@10:     audio_chunks = buf_size / s->chunk_size;
yading@10: 
yading@10:     /* get output buffer */
yading@10:     frame->nb_samples = ((silent_chunks + audio_chunks) * avctx->block_align) /
yading@10:                         avctx->channels;
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10:     output_samples_u8  =            frame->data[0];
yading@10:     output_samples_s16 = (int16_t *)frame->data[0];
yading@10: 
yading@10:     /* decode silent chunks */
yading@10:     if (silent_chunks > 0) {
yading@10:         int silent_size = avctx->block_align * silent_chunks;
yading@10:         if (s->out_bps == 2) {
yading@10:             memset(output_samples_s16, 0x00, silent_size * 2);
yading@10:             output_samples_s16 += silent_size;
yading@10:         } else {
yading@10:             memset(output_samples_u8,  0x80, silent_size);
yading@10:             output_samples_u8 += silent_size;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     /* decode audio chunks */
yading@10:     if (audio_chunks > 0) {
yading@10:         buf_end = buf + buf_size;
yading@10:         while (buf_end - buf >= s->chunk_size) {
yading@10:             if (s->out_bps == 2) {
yading@10:                 decode_audio_s16(output_samples_s16, buf, s->chunk_size,
yading@10:                                  avctx->channels);
yading@10:                 output_samples_s16 += avctx->block_align;
yading@10:             } else {
yading@10:                 memcpy(output_samples_u8, buf, s->chunk_size);
yading@10:                 output_samples_u8  += avctx->block_align;
yading@10:             }
yading@10:             buf += s->chunk_size;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     *got_frame_ptr = 1;
yading@10: 
yading@10:     return avpkt->size;
yading@10: }
yading@10: 
yading@10: 
yading@10: /*
yading@10:  * Public Data Structures
yading@10:  */
yading@10: 
yading@10: AVCodec ff_vmdvideo_decoder = {
yading@10:     .name           = "vmdvideo",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_VMDVIDEO,
yading@10:     .priv_data_size = sizeof(VmdVideoContext),
yading@10:     .init           = vmdvideo_decode_init,
yading@10:     .close          = vmdvideo_decode_end,
yading@10:     .decode         = vmdvideo_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Sierra VMD video"),
yading@10: };
yading@10: 
yading@10: AVCodec ff_vmdaudio_decoder = {
yading@10:     .name           = "vmdaudio",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_VMDAUDIO,
yading@10:     .priv_data_size = sizeof(VmdAudioContext),
yading@10:     .init           = vmdaudio_decode_init,
yading@10:     .decode         = vmdaudio_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Sierra VMD audio"),
yading@10: };