* Shorten decoder
* Copyright (c) 2005 Jeff Muizelaar
*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
*
- * Libav is free software; you can redistribute it and/or
+ * 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.
*
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <limits.h>
#include "avcodec.h"
+#include "bytestream.h"
#include "get_bits.h"
#include "golomb.h"
int blocksize;
int bitindex;
int32_t lpcqoffset;
+ int got_header;
+ int got_quit_command;
} ShortenContext;
static av_cold int shorten_decode_init(AVCodecContext * avctx)
s->offset[chan][i] = mean;
}
-static inline int get_le32(GetBitContext *gb)
+static int decode_wave_header(AVCodecContext *avctx, const uint8_t *header,
+ int header_size)
{
- return av_bswap32(get_bits_long(gb, 32));
-}
-
-static inline short get_le16(GetBitContext *gb)
-{
- return av_bswap16(get_bits_long(gb, 16));
-}
-
-static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
-{
- GetBitContext hb;
int len;
short wave_format;
- init_get_bits(&hb, header, header_size*8);
- if (get_le32(&hb) != MKTAG('R','I','F','F')) {
+
+ if (bytestream_get_le32(&header) != MKTAG('R','I','F','F')) {
av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
return -1;
}
- skip_bits_long(&hb, 32); /* chunk_size */
+ header += 4; /* chunk size */;
- if (get_le32(&hb) != MKTAG('W','A','V','E')) {
+ if (bytestream_get_le32(&header) != MKTAG('W','A','V','E')) {
av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
return -1;
}
- while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
- len = get_le32(&hb);
- skip_bits(&hb, 8*len);
+ while (bytestream_get_le32(&header) != MKTAG('f','m','t',' ')) {
+ len = bytestream_get_le32(&header);
+ header += len;
}
- len = get_le32(&hb);
+ len = bytestream_get_le32(&header);
if (len < 16) {
av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
return -1;
}
- wave_format = get_le16(&hb);
+ wave_format = bytestream_get_le16(&header);
switch (wave_format) {
case WAVE_FORMAT_PCM:
return -1;
}
- skip_bits(&hb, 16); // skip channels (already got from shorten header)
- avctx->sample_rate = get_le32(&hb);
- skip_bits(&hb, 32); // skip bit rate (represents original uncompressed bit rate)
- skip_bits(&hb, 16); // skip block align (not needed)
- avctx->bits_per_coded_sample = get_le16(&hb);
+ header += 2; // skip channels (already got from shorten header)
+ avctx->sample_rate = bytestream_get_le32(&header);
+ header += 4; // skip bit rate (represents original uncompressed bit rate)
+ header += 2; // skip block align (not needed)
+ avctx->bits_per_coded_sample = bytestream_get_le16(&header);
if (avctx->bits_per_coded_sample != 16) {
av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
return 0;
}
-static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
+static void interleave_buffer(int16_t *samples, int nchan, int blocksize,
+ int32_t **buffer)
+{
int i, chan;
for (i=0; i<blocksize; i++)
for (chan=0; chan < nchan; chan++)
- *samples++ = FFMIN(buffer[chan][i], 32768);
- return samples;
+ *samples++ = av_clip_int16(buffer[chan][i]);
}
-static int decode_subframe_lpc(ShortenContext *s, int channel,
+static const int fixed_coeffs[3][3] = {
+ { 1, 0, 0 },
+ { 2, -1, 0 },
+ { 3, -3, 1 }
+};
+
+static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
int residual_size, int32_t coffset)
{
- int pred_order, sum, i, j;
- int *coeffs = s->coeffs;
-
- /* read/validate prediction order */
- pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
- if (pred_order > s->nwrap) {
- av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n", pred_order);
- return AVERROR(EINVAL);
+ int pred_order, sum, qshift, init_sum, i, j;
+ const int *coeffs;
+
+ if (command == FN_QLPC) {
+ /* read/validate prediction order */
+ pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
+ if (pred_order > s->nwrap) {
+ av_log(s->avctx, AV_LOG_ERROR, "invalid pred_order %d\n", pred_order);
+ return AVERROR(EINVAL);
+ }
+ /* read LPC coefficients */
+ for (i=0; i<pred_order; i++)
+ s->coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
+ coeffs = s->coeffs;
+
+ qshift = LPCQUANT;
+ } else {
+ /* fixed LPC coeffs */
+ pred_order = command;
+ coeffs = fixed_coeffs[pred_order-1];
+ qshift = 0;
}
- /* read LPC coefficients */
- for (i=0; i<pred_order; i++)
- coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
/* subtract offset from previous samples to use in prediction */
- if (coffset)
+ if (command == FN_QLPC && coffset)
for (i = -pred_order; i < 0; i++)
s->decoded[channel][i] -= coffset;
/* decode residual and do LPC prediction */
+ init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
for (i=0; i < s->blocksize; i++) {
- sum = s->lpcqoffset;
+ sum = init_sum;
for (j=0; j<pred_order; j++)
sum += coeffs[j] * s->decoded[channel][i-j-1];
- s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
+ s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> qshift);
}
/* add offset to current samples */
- if (coffset != 0)
+ if (command == FN_QLPC && coffset)
for (i = 0; i < s->blocksize; i++)
s->decoded[channel][i] += coffset;
s->cur_chan = 0;
s->bitshift = 0;
+ s->got_header = 1;
+
return 0;
}
int16_t *samples = data;
int ret;
+ /* allocate internal bitstream buffer */
if(s->max_framesize == 0){
void *tmp_ptr;
s->max_framesize= 1024; // should hopefully be enough for the first header
s->bitstream = tmp_ptr;
}
+ /* append current packet data to bitstream buffer */
if(1 && s->max_framesize){//FIXME truncated
buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
input_buf_size= buf_size;
memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
s->bitstream_index=0;
}
- memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
+ if (buf)
+ memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
buf= &s->bitstream[s->bitstream_index];
buf_size += s->bitstream_size;
s->bitstream_size= buf_size;
- if(buf_size < s->max_framesize){
+ /* do not decode until buffer has at least max_framesize bytes or
+ the end of the file has been reached */
+ if (buf_size < s->max_framesize && avpkt->data) {
*data_size = 0;
return input_buf_size;
}
}
+ /* init and position bitstream reader */
init_get_bits(&s->gb, buf, buf_size*8);
skip_bits(&s->gb, s->bitindex);
- if (!s->blocksize)
- {
+
+ /* process header or next subblock */
+ if (!s->got_header) {
if ((ret = read_header(s)) < 0)
return ret;
*data_size = 0;
+ goto finish_frame;
}
- else
- {
+
+ /* if quit command was read previously, don't decode anything */
+ if (s->got_quit_command) {
+ *data_size = 0;
+ return avpkt->size;
+ }
+
+ s->cur_chan = 0;
+ while (s->cur_chan < s->channels) {
int cmd;
int len;
+
+ if (get_bits_left(&s->gb) < 3+FNSIZE) {
+ *data_size = 0;
+ break;
+ }
+
cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
if (cmd > FN_VERBATIM) {
av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
- if (s->bitstream_size > 0) {
- s->bitstream_index++;
- s->bitstream_size--;
- }
- return -1;
+ *data_size = 0;
+ break;
}
if (!is_audio_command[cmd]) {
break;
}
case FN_QUIT:
+ s->got_quit_command = 1;
break;
}
- *data_size = 0;
+ if (cmd == FN_BLOCKSIZE || cmd == FN_QUIT) {
+ *data_size = 0;
+ break;
+ }
} else {
/* process audio command */
int residual_size = 0;
int channel = s->cur_chan;
int32_t coffset;
+
+ /* get Rice code for residual decoding */
if (cmd != FN_ZERO) {
residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
/* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
residual_size--;
}
+ /* calculate sample offset using means from previous blocks */
if (s->nmean == 0)
coffset = s->offset[channel][0];
else {
if (s->version >= 2)
coffset >>= FFMIN(1, s->bitshift);
}
- switch (cmd) {
- case FN_ZERO:
- for (i=0; i<s->blocksize; i++)
- s->decoded[channel][i] = 0;
- break;
- case FN_DIFF0:
- for (i=0; i<s->blocksize; i++)
- s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
- break;
- case FN_DIFF1:
- for (i=0; i<s->blocksize; i++)
- s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
- break;
- case FN_DIFF2:
- for (i=0; i<s->blocksize; i++)
- s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
- - s->decoded[channel][i-2];
- break;
- case FN_DIFF3:
- for (i=0; i<s->blocksize; i++)
- s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
- - 3*s->decoded[channel][i-2]
- + s->decoded[channel][i-3];
- break;
- case FN_QLPC:
- if ((ret = decode_subframe_lpc(s, channel, residual_size, coffset)) < 0)
- return ret;
- break;
+
+ /* decode samples for this channel */
+ if (cmd == FN_ZERO) {
+ for (i=0; i<s->blocksize; i++)
+ s->decoded[channel][i] = 0;
+ } else {
+ if ((ret = decode_subframe_lpc(s, cmd, channel, residual_size, coffset)) < 0)
+ return ret;
}
+
+ /* update means with info from the current block */
if (s->nmean > 0) {
int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
for (i=0; i<s->blocksize; i++)
else
s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
}
+
+ /* copy wrap samples for use with next block */
for (i=-s->nwrap; i<0; i++)
s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
+ /* shift samples to add in unused zero bits which were removed
+ during encoding */
fix_bitshift(s, s->decoded[channel]);
+ /* if this is the last channel in the block, output the samples */
s->cur_chan++;
if (s->cur_chan == s->channels) {
- samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
- s->cur_chan = 0;
- *data_size = (int8_t *)samples - (int8_t *)data;
- } else {
- *data_size = 0;
+ int out_size = s->blocksize * s->channels *
+ av_get_bytes_per_sample(avctx->sample_fmt);
+ if (*data_size < out_size) {
+ av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
+ return AVERROR(EINVAL);
+ }
+ interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
+ *data_size = out_size;
}
}
}
+ if (s->cur_chan < s->channels)
+ *data_size = 0;
+finish_frame:
s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
i= (get_bits_count(&s->gb))/8;
if (i > buf_size) {
.init = shorten_decode_init,
.close = shorten_decode_close,
.decode = shorten_decode_frame,
+ .capabilities = CODEC_CAP_DELAY,
.long_name= NULL_IF_CONFIG_SMALL("Shorten"),
};
projects / ffmpeg / blobdiff