yading@10: /*
yading@10:  * Shorten decoder
yading@10:  * Copyright (c) 2005 Jeff Muizelaar
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:  * Shorten decoder
yading@10:  * @author Jeff Muizelaar
yading@10:  *
yading@10:  */
yading@10: 
yading@10: #include <limits.h>
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "get_bits.h"
yading@10: #include "golomb.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define MAX_CHANNELS 8
yading@10: #define MAX_BLOCKSIZE 65535
yading@10: 
yading@10: #define OUT_BUFFER_SIZE 16384
yading@10: 
yading@10: #define ULONGSIZE 2
yading@10: 
yading@10: #define WAVE_FORMAT_PCM 0x0001
yading@10: 
yading@10: #define DEFAULT_BLOCK_SIZE 256
yading@10: 
yading@10: #define TYPESIZE 4
yading@10: #define CHANSIZE 0
yading@10: #define LPCQSIZE 2
yading@10: #define ENERGYSIZE 3
yading@10: #define BITSHIFTSIZE 2
yading@10: 
yading@10: #define TYPE_S8    1
yading@10: #define TYPE_U8    2
yading@10: #define TYPE_S16HL 3
yading@10: #define TYPE_U16HL 4
yading@10: #define TYPE_S16LH 5
yading@10: #define TYPE_U16LH 6
yading@10: 
yading@10: #define NWRAP 3
yading@10: #define NSKIPSIZE 1
yading@10: 
yading@10: #define LPCQUANT 5
yading@10: #define V2LPCQOFFSET (1 << LPCQUANT)
yading@10: 
yading@10: #define FNSIZE 2
yading@10: #define FN_DIFF0        0
yading@10: #define FN_DIFF1        1
yading@10: #define FN_DIFF2        2
yading@10: #define FN_DIFF3        3
yading@10: #define FN_QUIT         4
yading@10: #define FN_BLOCKSIZE    5
yading@10: #define FN_BITSHIFT     6
yading@10: #define FN_QLPC         7
yading@10: #define FN_ZERO         8
yading@10: #define FN_VERBATIM     9
yading@10: 
yading@10: /** indicates if the FN_* command is audio or non-audio */
yading@10: static const uint8_t is_audio_command[10] = { 1, 1, 1, 1, 0, 0, 0, 1, 1, 0 };
yading@10: 
yading@10: #define VERBATIM_CKSIZE_SIZE 5
yading@10: #define VERBATIM_BYTE_SIZE 8
yading@10: #define CANONICAL_HEADER_SIZE 44
yading@10: 
yading@10: typedef struct ShortenContext {
yading@10:     AVCodecContext *avctx;
yading@10:     GetBitContext gb;
yading@10: 
yading@10:     int min_framesize, max_framesize;
yading@10:     unsigned channels;
yading@10: 
yading@10:     int32_t *decoded[MAX_CHANNELS];
yading@10:     int32_t *decoded_base[MAX_CHANNELS];
yading@10:     int32_t *offset[MAX_CHANNELS];
yading@10:     int *coeffs;
yading@10:     uint8_t *bitstream;
yading@10:     int bitstream_size;
yading@10:     int bitstream_index;
yading@10:     unsigned int allocated_bitstream_size;
yading@10:     int header_size;
yading@10:     uint8_t header[OUT_BUFFER_SIZE];
yading@10:     int version;
yading@10:     int cur_chan;
yading@10:     int bitshift;
yading@10:     int nmean;
yading@10:     int internal_ftype;
yading@10:     int nwrap;
yading@10:     int blocksize;
yading@10:     int bitindex;
yading@10:     int32_t lpcqoffset;
yading@10:     int got_header;
yading@10:     int got_quit_command;
yading@10: } ShortenContext;
yading@10: 
yading@10: static av_cold int shorten_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     ShortenContext *s = avctx->priv_data;
yading@10:     s->avctx          = avctx;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int allocate_buffers(ShortenContext *s)
yading@10: {
yading@10:     int i, chan;
yading@10:     int *coeffs;
yading@10:     void *tmp_ptr;
yading@10: 
yading@10:     for (chan = 0; chan < s->channels; chan++) {
yading@10:         if (FFMAX(1, s->nmean) >= UINT_MAX / sizeof(int32_t)) {
yading@10:             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10:         if (s->blocksize + s->nwrap >= UINT_MAX / sizeof(int32_t) ||
yading@10:             s->blocksize + s->nwrap <= (unsigned)s->nwrap) {
yading@10:             av_log(s->avctx, AV_LOG_ERROR,
yading@10:                    "s->blocksize + s->nwrap too large\n");
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10: 
yading@10:         tmp_ptr =
yading@10:             av_realloc(s->offset[chan], sizeof(int32_t) * FFMAX(1, s->nmean));
yading@10:         if (!tmp_ptr)
yading@10:             return AVERROR(ENOMEM);
yading@10:         s->offset[chan] = tmp_ptr;
yading@10: 
yading@10:         tmp_ptr = av_realloc(s->decoded_base[chan], (s->blocksize + s->nwrap) *
yading@10:                              sizeof(s->decoded_base[0][0]));
yading@10:         if (!tmp_ptr)
yading@10:             return AVERROR(ENOMEM);
yading@10:         s->decoded_base[chan] = tmp_ptr;
yading@10:         for (i = 0; i < s->nwrap; i++)
yading@10:             s->decoded_base[chan][i] = 0;
yading@10:         s->decoded[chan] = s->decoded_base[chan] + s->nwrap;
yading@10:     }
yading@10: 
yading@10:     coeffs = av_realloc(s->coeffs, s->nwrap * sizeof(*s->coeffs));
yading@10:     if (!coeffs)
yading@10:         return AVERROR(ENOMEM);
yading@10:     s->coeffs = coeffs;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static inline unsigned int get_uint(ShortenContext *s, int k)
yading@10: {
yading@10:     if (s->version != 0)
yading@10:         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
yading@10:     return get_ur_golomb_shorten(&s->gb, k);
yading@10: }
yading@10: 
yading@10: static void fix_bitshift(ShortenContext *s, int32_t *buffer)
yading@10: {
yading@10:     int i;
yading@10: 
yading@10:     if (s->bitshift != 0)
yading@10:         for (i = 0; i < s->blocksize; i++)
yading@10:             buffer[i] <<= s->bitshift;
yading@10: }
yading@10: 
yading@10: static int init_offset(ShortenContext *s)
yading@10: {
yading@10:     int32_t mean = 0;
yading@10:     int chan, i;
yading@10:     int nblock = FFMAX(1, s->nmean);
yading@10:     /* initialise offset */
yading@10:     switch (s->internal_ftype) {
yading@10:     case TYPE_U8:
yading@10:         s->avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
yading@10:         mean = 0x80;
yading@10:         break;
yading@10:     case TYPE_S16HL:
yading@10:     case TYPE_S16LH:
yading@10:         s->avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
yading@10:         break;
yading@10:     default:
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "unknown audio type\n");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     for (chan = 0; chan < s->channels; chan++)
yading@10:         for (i = 0; i < nblock; i++)
yading@10:             s->offset[chan][i] = mean;
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header,
yading@10:                               int header_size)
yading@10: {
yading@10:     int len, bps;
yading@10:     short wave_format;
yading@10:     const uint8_t *end= header + header_size;
yading@10: 
yading@10:     if (bytestream_get_le32(&header) != MKTAG('R', 'I', 'F', 'F')) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     header += 4; /* chunk size */
yading@10: 
yading@10:     if (bytestream_get_le32(&header) != MKTAG('W', 'A', 'V', 'E')) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     while (bytestream_get_le32(&header) != MKTAG('f', 'm', 't', ' ')) {
yading@10:         len     = bytestream_get_le32(&header);
yading@10:         if (len<0 || end - header - 8 < len)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         header += len;
yading@10:     }
yading@10:     len = bytestream_get_le32(&header);
yading@10: 
yading@10:     if (len < 16) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     wave_format = bytestream_get_le16(&header);
yading@10: 
yading@10:     switch (wave_format) {
yading@10:     case WAVE_FORMAT_PCM:
yading@10:         break;
yading@10:     default:
yading@10:         av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
yading@10:         return AVERROR(ENOSYS);
yading@10:     }
yading@10: 
yading@10:     header += 2;        // skip channels    (already got from shorten header)
yading@10:     avctx->sample_rate = bytestream_get_le32(&header);
yading@10:     header += 4;        // skip bit rate    (represents original uncompressed bit rate)
yading@10:     header += 2;        // skip block align (not needed)
yading@10:     bps     = bytestream_get_le16(&header);
yading@10:     avctx->bits_per_coded_sample = bps;
yading@10: 
yading@10:     if (bps != 16 && bps != 8) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample: %d\n", bps);
yading@10:         return AVERROR(ENOSYS);
yading@10:     }
yading@10: 
yading@10:     len -= 16;
yading@10:     if (len > 0)
yading@10:         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static const int fixed_coeffs[3][3] = {
yading@10:     { 1,  0,  0 },
yading@10:     { 2, -1,  0 },
yading@10:     { 3, -3,  1 }
yading@10: };
yading@10: 
yading@10: static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
yading@10:                                int residual_size, int32_t coffset)
yading@10: {
yading@10:     int pred_order, sum, qshift, init_sum, i, j;
yading@10:     const int *coeffs;
yading@10: 
yading@10:     if (command == FN_QLPC) {
yading@10:         /* read/validate prediction order */
yading@10:         pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
yading@10:         if (pred_order > s->nwrap) {
yading@10:             av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n",
yading@10:                    pred_order);
yading@10:             return AVERROR(EINVAL);
yading@10:         }
yading@10:         /* read LPC coefficients */
yading@10:         for (i = 0; i < pred_order; i++)
yading@10:             s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
yading@10:         coeffs = s->coeffs;
yading@10: 
yading@10:         qshift = LPCQUANT;
yading@10:     } else {
yading@10:         /* fixed LPC coeffs */
yading@10:         pred_order = command;
yading@10:         coeffs     = fixed_coeffs[pred_order - 1];
yading@10:         qshift     = 0;
yading@10:     }
yading@10: 
yading@10:     /* subtract offset from previous samples to use in prediction */
yading@10:     if (command == FN_QLPC && coffset)
yading@10:         for (i = -pred_order; i < 0; i++)
yading@10:             s->decoded[channel][i] -= coffset;
yading@10: 
yading@10:     /* decode residual and do LPC prediction */
yading@10:     init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
yading@10:     for (i = 0; i < s->blocksize; i++) {
yading@10:         sum = init_sum;
yading@10:         for (j = 0; j < pred_order; j++)
yading@10:             sum += coeffs[j] * s->decoded[channel][i - j - 1];
yading@10:         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) +
yading@10:                                  (sum >> qshift);
yading@10:     }
yading@10: 
yading@10:     /* add offset to current samples */
yading@10:     if (command == FN_QLPC && coffset)
yading@10:         for (i = 0; i < s->blocksize; i++)
yading@10:             s->decoded[channel][i] += coffset;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int read_header(ShortenContext *s)
yading@10: {
yading@10:     int i, ret;
yading@10:     int maxnlpc = 0;
yading@10:     /* shorten signature */
yading@10:     if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     s->lpcqoffset     = 0;
yading@10:     s->blocksize      = DEFAULT_BLOCK_SIZE;
yading@10:     s->nmean          = -1;
yading@10:     s->version        = get_bits(&s->gb, 8);
yading@10:     s->internal_ftype = get_uint(s, TYPESIZE);
yading@10: 
yading@10:     s->channels = get_uint(s, CHANSIZE);
yading@10:     if (!s->channels) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "No channels reported\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10:     if (s->channels > MAX_CHANNELS) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
yading@10:         s->channels = 0;
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10:     s->avctx->channels = s->channels;
yading@10: 
yading@10:     /* get blocksize if version > 0 */
yading@10:     if (s->version > 0) {
yading@10:         int skip_bytes;
yading@10:         unsigned blocksize;
yading@10: 
yading@10:         blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
yading@10:         if (!blocksize || blocksize > MAX_BLOCKSIZE) {
yading@10:             av_log(s->avctx, AV_LOG_ERROR,
yading@10:                    "invalid or unsupported block size: %d\n",
yading@10:                    blocksize);
yading@10:             return AVERROR(EINVAL);
yading@10:         }
yading@10:         s->blocksize = blocksize;
yading@10: 
yading@10:         maxnlpc  = get_uint(s, LPCQSIZE);
yading@10:         s->nmean = get_uint(s, 0);
yading@10: 
yading@10:         skip_bytes = get_uint(s, NSKIPSIZE);
yading@10:         for (i = 0; i < skip_bytes; i++)
yading@10:             skip_bits(&s->gb, 8);
yading@10:     }
yading@10:     s->nwrap = FFMAX(NWRAP, maxnlpc);
yading@10: 
yading@10:     if ((ret = allocate_buffers(s)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     if ((ret = init_offset(s)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     if (s->version > 1)
yading@10:         s->lpcqoffset = V2LPCQOFFSET;
yading@10: 
yading@10:     if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR,
yading@10:                "missing verbatim section at beginning of stream\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
yading@10:     if (s->header_size >= OUT_BUFFER_SIZE ||
yading@10:         s->header_size < CANONICAL_HEADER_SIZE) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n",
yading@10:                s->header_size);
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     for (i = 0; i < s->header_size; i++)
yading@10:         s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
yading@10: 
yading@10:     if ((ret = decode_wave_header(s->avctx, s->header, s->header_size)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     s->cur_chan = 0;
yading@10:     s->bitshift = 0;
yading@10: 
yading@10:     s->got_header = 1;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int shorten_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:     int buf_size       = avpkt->size;
yading@10:     ShortenContext *s  = avctx->priv_data;
yading@10:     int i, input_buf_size = 0;
yading@10:     int ret;
yading@10: 
yading@10:     /* allocate internal bitstream buffer */
yading@10:     if (s->max_framesize == 0) {
yading@10:         void *tmp_ptr;
yading@10:         s->max_framesize = 8192; // should hopefully be enough for the first header
yading@10:         tmp_ptr = av_fast_realloc(s->bitstream, &s->allocated_bitstream_size,
yading@10:                                   s->max_framesize);
yading@10:         if (!tmp_ptr) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "error allocating bitstream buffer\n");
yading@10:             return AVERROR(ENOMEM);
yading@10:         }
yading@10:         s->bitstream = tmp_ptr;
yading@10:     }
yading@10: 
yading@10:     /* append current packet data to bitstream buffer */
yading@10:     if (1 && s->max_framesize) { //FIXME truncated
yading@10:         buf_size       = FFMIN(buf_size, s->max_framesize - s->bitstream_size);
yading@10:         input_buf_size = buf_size;
yading@10: 
yading@10:         if (s->bitstream_index + s->bitstream_size + buf_size >
yading@10:             s->allocated_bitstream_size) {
yading@10:             memmove(s->bitstream, &s->bitstream[s->bitstream_index],
yading@10:                     s->bitstream_size);
yading@10:             s->bitstream_index = 0;
yading@10:         }
yading@10:         if (buf)
yading@10:             memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf,
yading@10:                    buf_size);
yading@10:         buf               = &s->bitstream[s->bitstream_index];
yading@10:         buf_size         += s->bitstream_size;
yading@10:         s->bitstream_size = buf_size;
yading@10: 
yading@10:         /* do not decode until buffer has at least max_framesize bytes or
yading@10:          * the end of the file has been reached */
yading@10:         if (buf_size < s->max_framesize && avpkt->data) {
yading@10:             *got_frame_ptr = 0;
yading@10:             return input_buf_size;
yading@10:         }
yading@10:     }
yading@10:     /* init and position bitstream reader */
yading@10:     init_get_bits(&s->gb, buf, buf_size * 8);
yading@10:     skip_bits(&s->gb, s->bitindex);
yading@10: 
yading@10:     /* process header or next subblock */
yading@10:     if (!s->got_header) {
yading@10:         if ((ret = read_header(s)) < 0)
yading@10:             return ret;
yading@10:         *got_frame_ptr = 0;
yading@10:         goto finish_frame;
yading@10:     }
yading@10: 
yading@10:     /* if quit command was read previously, don't decode anything */
yading@10:     if (s->got_quit_command) {
yading@10:         *got_frame_ptr = 0;
yading@10:         return avpkt->size;
yading@10:     }
yading@10: 
yading@10:     s->cur_chan = 0;
yading@10:     while (s->cur_chan < s->channels) {
yading@10:         unsigned cmd;
yading@10:         int len;
yading@10: 
yading@10:         if (get_bits_left(&s->gb) < 3 + FNSIZE) {
yading@10:             *got_frame_ptr = 0;
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
yading@10: 
yading@10:         if (cmd > FN_VERBATIM) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
yading@10:             *got_frame_ptr = 0;
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         if (!is_audio_command[cmd]) {
yading@10:             /* process non-audio command */
yading@10:             switch (cmd) {
yading@10:             case FN_VERBATIM:
yading@10:                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
yading@10:                 while (len--)
yading@10:                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
yading@10:                 break;
yading@10:             case FN_BITSHIFT:
yading@10:                 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
yading@10:                 break;
yading@10:             case FN_BLOCKSIZE: {
yading@10:                 unsigned blocksize = get_uint(s, av_log2(s->blocksize));
yading@10:                 if (blocksize > s->blocksize) {
yading@10:                     av_log(avctx, AV_LOG_ERROR,
yading@10:                            "Increasing block size is not supported\n");
yading@10:                     return AVERROR_PATCHWELCOME;
yading@10:                 }
yading@10:                 if (!blocksize || blocksize > MAX_BLOCKSIZE) {
yading@10:                     av_log(avctx, AV_LOG_ERROR, "invalid or unsupported "
yading@10:                                                 "block size: %d\n", blocksize);
yading@10:                     return AVERROR(EINVAL);
yading@10:                 }
yading@10:                 s->blocksize = blocksize;
yading@10:                 break;
yading@10:             }
yading@10:             case FN_QUIT:
yading@10:                 s->got_quit_command = 1;
yading@10:                 break;
yading@10:             }
yading@10:             if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) {
yading@10:                 *got_frame_ptr = 0;
yading@10:                 break;
yading@10:             }
yading@10:         } else {
yading@10:             /* process audio command */
yading@10:             int residual_size = 0;
yading@10:             int channel = s->cur_chan;
yading@10:             int32_t coffset;
yading@10: 
yading@10:             /* get Rice code for residual decoding */
yading@10:             if (cmd != FN_ZERO) {
yading@10:                 residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
yading@10:                 /* This is a hack as version 0 differed in the definition
yading@10:                  * of get_sr_golomb_shorten(). */
yading@10:                 if (s->version == 0)
yading@10:                     residual_size--;
yading@10:             }
yading@10: 
yading@10:             /* calculate sample offset using means from previous blocks */
yading@10:             if (s->nmean == 0)
yading@10:                 coffset = s->offset[channel][0];
yading@10:             else {
yading@10:                 int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
yading@10:                 for (i = 0; i < s->nmean; i++)
yading@10:                     sum += s->offset[channel][i];
yading@10:                 coffset = sum / s->nmean;
yading@10:                 if (s->version >= 2)
yading@10:                     coffset = s->bitshift == 0 ? coffset : coffset >> s->bitshift - 1 >> 1;
yading@10:             }
yading@10: 
yading@10:             /* decode samples for this channel */
yading@10:             if (cmd == FN_ZERO) {
yading@10:                 for (i = 0; i < s->blocksize; i++)
yading@10:                     s->decoded[channel][i] = 0;
yading@10:             } else {
yading@10:                 if ((ret = decode_subframe_lpc(s, cmd, channel,
yading@10:                                                residual_size, coffset)) < 0)
yading@10:                     return ret;
yading@10:             }
yading@10: 
yading@10:             /* update means with info from the current block */
yading@10:             if (s->nmean > 0) {
yading@10:                 int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
yading@10:                 for (i = 0; i < s->blocksize; i++)
yading@10:                     sum += s->decoded[channel][i];
yading@10: 
yading@10:                 for (i = 1; i < s->nmean; i++)
yading@10:                     s->offset[channel][i - 1] = s->offset[channel][i];
yading@10: 
yading@10:                 if (s->version < 2)
yading@10:                     s->offset[channel][s->nmean - 1] = sum / s->blocksize;
yading@10:                 else
yading@10:                     s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
yading@10:             }
yading@10: 
yading@10:             /* copy wrap samples for use with next block */
yading@10:             for (i = -s->nwrap; i < 0; i++)
yading@10:                 s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
yading@10: 
yading@10:             /* shift samples to add in unused zero bits which were removed
yading@10:              * during encoding */
yading@10:             fix_bitshift(s, s->decoded[channel]);
yading@10: 
yading@10:             /* if this is the last channel in the block, output the samples */
yading@10:             s->cur_chan++;
yading@10:             if (s->cur_chan == s->channels) {
yading@10:                 uint8_t *samples_u8;
yading@10:                 int16_t *samples_s16;
yading@10:                 int chan;
yading@10: 
yading@10:                 /* get output buffer */
yading@10:                 frame->nb_samples = s->blocksize;
yading@10:                 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:                     return ret;
yading@10: 
yading@10:                 for (chan = 0; chan < s->channels; chan++) {
yading@10:                     samples_u8  = ((uint8_t **)frame->extended_data)[chan];
yading@10:                     samples_s16 = ((int16_t **)frame->extended_data)[chan];
yading@10:                     for (i = 0; i < s->blocksize; i++) {
yading@10:                         switch (s->internal_ftype) {
yading@10:                         case TYPE_U8:
yading@10:                             *samples_u8++ = av_clip_uint8(s->decoded[chan][i]);
yading@10:                             break;
yading@10:                         case TYPE_S16HL:
yading@10:                         case TYPE_S16LH:
yading@10:                             *samples_s16++ = av_clip_int16(s->decoded[chan][i]);
yading@10:                             break;
yading@10:                         }
yading@10:                     }
yading@10:                 }
yading@10: 
yading@10:                 *got_frame_ptr = 1;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     if (s->cur_chan < s->channels)
yading@10:         *got_frame_ptr = 0;
yading@10: 
yading@10: finish_frame:
yading@10:     s->bitindex = get_bits_count(&s->gb) - 8 * (get_bits_count(&s->gb) / 8);
yading@10:     i           = get_bits_count(&s->gb) / 8;
yading@10:     if (i > buf_size) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
yading@10:         s->bitstream_size  = 0;
yading@10:         s->bitstream_index = 0;
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10:     if (s->bitstream_size) {
yading@10:         s->bitstream_index += i;
yading@10:         s->bitstream_size  -= i;
yading@10:         return input_buf_size;
yading@10:     } else
yading@10:         return i;
yading@10: }
yading@10: 
yading@10: static av_cold int shorten_decode_close(AVCodecContext *avctx)
yading@10: {
yading@10:     ShortenContext *s = avctx->priv_data;
yading@10:     int i;
yading@10: 
yading@10:     for (i = 0; i < s->channels; i++) {
yading@10:         s->decoded[i] = NULL;
yading@10:         av_freep(&s->decoded_base[i]);
yading@10:         av_freep(&s->offset[i]);
yading@10:     }
yading@10:     av_freep(&s->bitstream);
yading@10:     av_freep(&s->coeffs);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_shorten_decoder = {
yading@10:     .name           = "shorten",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_SHORTEN,
yading@10:     .priv_data_size = sizeof(ShortenContext),
yading@10:     .init           = shorten_decode_init,
yading@10:     .close          = shorten_decode_close,
yading@10:     .decode         = shorten_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Shorten"),
yading@10:     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
yading@10:                                                       AV_SAMPLE_FMT_U8P,
yading@10:                                                       AV_SAMPLE_FMT_NONE },
yading@10: };