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g722dec: Signal skipping the lower bits via AVOptions instead of bits_per_coded_sample

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This avoids using bits_per_coded_sample for this information.
bits_per_coded_sample should be 4 for this codec normally,
since two samples are encoded into one 8 bit codeword.

In principle, this might be info that needs to be passed from
a demuxer, and in that case, a private AVOption isn't the best
choice, but no such samples are available at the moment, so
that use case is purely theoretical at the moment.

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2011-12-03 19:54:20 +02:00
parent 0bafe04917
commit 6fcbb0f553
2 changed files with 19 additions and 15 deletions
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2
libavcodec/g722.h
View File

@ -31,7 +31,9 @@
#define PREV_SAMPLES_BUF_SIZE 1024
typedef struct {
const AVClass *class;
AVFrame frame;
int bits_per_codeword;
int16_t prev_samples[PREV_SAMPLES_BUF_SIZE]; ///< memory of past decoded samples
int prev_samples_pos; ///< the number of values in prev_samples

32
libavcodec/g722dec.c
View File

@ -37,6 +37,21 @@
#include "avcodec.h"
#include "get_bits.h"
#include "g722.h"
#include "libavutil/opt.h"
#define OFFSET(x) offsetof(G722Context, x)
#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { 8 }, 6, 8, AD },
{ NULL }
};
static const AVClass g722_decoder_class = {
.class_name = "g722 decoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static av_cold int g722_decode_init(AVCodecContext * avctx)
{
@ -48,20 +63,6 @@ static av_cold int g722_decode_init(AVCodecContext * avctx)
}
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
switch (avctx->bits_per_coded_sample) {
case 8:
case 7:
case 6:
break;
default:
av_log(avctx, AV_LOG_WARNING, "Unsupported bits_per_coded_sample [%d], "
"assuming 8\n",
avctx->bits_per_coded_sample);
case 0:
avctx->bits_per_coded_sample = 8;
break;
}
c->band[0].scale_factor = 8;
c->band[1].scale_factor = 2;
c->prev_samples_pos = 22;
@ -89,7 +90,7 @@ static int g722_decode_frame(AVCodecContext *avctx, void *data,
G722Context *c = avctx->priv_data;
int16_t *out_buf;
int j, ret;
const int skip = 8 - avctx->bits_per_coded_sample;
const int skip = 8 - c->bits_per_codeword;
const int16_t *quantizer_table = low_inv_quants[skip];
GetBitContext gb;
@ -149,4 +150,5 @@ AVCodec ff_adpcm_g722_decoder = {
.decode = g722_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
.priv_class = &g722_decoder_class,
};