*/
/**
- * @file mlp_parser.c
+ * @file libavcodec/mlp_parser.c
* MLP parser
*/
+#include <stdint.h>
+
#include "libavutil/crc.h"
-#include "bitstream.h"
+#include "get_bits.h"
#include "parser.h"
#include "mlp_parser.h"
+#include "mlp.h"
static const uint8_t mlp_quants[16] = {
16, 20, 24, 0, 0, 0, 0, 0,
return channels;
}
-static int crc_init = 0;
-static AVCRC crc_2D[1024];
-
-/** MLP uses checksums that seem to be based on the standard CRC algorithm,
- * but not (in implementation terms, the table lookup and XOR are reversed).
- * We can implement this behavior using a standard av_crc on all but the
- * last element, then XOR that with the last element.
- */
-
-static uint16_t mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
-{
- uint16_t crc;
-
- if (!crc_init) {
- av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
- crc_init = 1;
- }
-
- crc = av_crc(crc_2D, 0, buf, buf_size - 2);
- crc ^= AV_RL16(buf + buf_size - 2);
- return crc;
-}
-
/** Read a major sync info header - contains high level information about
* the stream - sample rate, channel arrangement etc. Most of this
* information is not actually necessary for decoding, only for playback.
+ * gb must be a freshly initialized GetBitContext with no bits read.
*/
-int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, const uint8_t *buf,
- unsigned int buf_size)
+int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
{
- GetBitContext gb;
int ratebits;
uint16_t checksum;
- if (buf_size < 28) {
- av_log(log, AV_LOG_ERROR, "Packet too short, unable to read major sync\n");
+ assert(get_bits_count(gb) == 0);
+
+ if (gb->size_in_bits < 28 << 3) {
+ av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");
return -1;
}
- checksum = mlp_checksum16(buf, 26);
- if (checksum != AV_RL16(buf+26)) {
- av_log(log, AV_LOG_ERROR, "Major sync info header checksum error\n");
+ checksum = ff_mlp_checksum16(gb->buffer, 26);
+ if (checksum != AV_RL16(gb->buffer+26)) {
+ av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");
return -1;
}
- init_get_bits(&gb, buf, buf_size * 8);
-
- if (get_bits_long(&gb, 24) != 0xf8726f) /* Sync words */
+ if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */
return -1;
- mh->stream_type = get_bits(&gb, 8);
+ mh->stream_type = get_bits(gb, 8);
if (mh->stream_type == 0xbb) {
- mh->group1_bits = mlp_quants[get_bits(&gb, 4)];
- mh->group2_bits = mlp_quants[get_bits(&gb, 4)];
+ mh->group1_bits = mlp_quants[get_bits(gb, 4)];
+ mh->group2_bits = mlp_quants[get_bits(gb, 4)];
- ratebits = get_bits(&gb, 4);
+ ratebits = get_bits(gb, 4);
mh->group1_samplerate = mlp_samplerate(ratebits);
- mh->group2_samplerate = mlp_samplerate(get_bits(&gb, 4));
+ mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));
- skip_bits(&gb, 11);
+ skip_bits(gb, 11);
- mh->channels_mlp = get_bits(&gb, 5);
+ mh->channels_mlp = get_bits(gb, 5);
} else if (mh->stream_type == 0xba) {
mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
mh->group2_bits = 0;
- ratebits = get_bits(&gb, 4);
+ ratebits = get_bits(gb, 4);
mh->group1_samplerate = mlp_samplerate(ratebits);
mh->group2_samplerate = 0;
- skip_bits(&gb, 8);
+ skip_bits(gb, 8);
- mh->channels_thd_stream1 = get_bits(&gb, 5);
+ mh->channels_thd_stream1 = get_bits(gb, 5);
- skip_bits(&gb, 2);
+ skip_bits(gb, 2);
- mh->channels_thd_stream2 = get_bits(&gb, 13);
+ mh->channels_thd_stream2 = get_bits(gb, 13);
} else
return -1;
mh->access_unit_size = 40 << (ratebits & 7);
mh->access_unit_size_pow2 = 64 << (ratebits & 7);
- skip_bits_long(&gb, 48);
+ skip_bits_long(gb, 48);
- mh->is_vbr = get_bits1(&gb);
+ mh->is_vbr = get_bits1(gb);
- mh->peak_bitrate = (get_bits(&gb, 15) * mh->group1_samplerate + 8) >> 4;
+ mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
- mh->num_substreams = get_bits(&gb, 4);
+ mh->num_substreams = get_bits(gb, 4);
- skip_bits_long(&gb, 4 + 11 * 8);
+ skip_bits_long(gb, 4 + 11 * 8);
return 0;
}
int num_substreams;
} MLPParseContext;
+static av_cold int mlp_init(AVCodecParserContext *s)
+{
+ ff_mlp_init_crc();
+ return 0;
+}
+
static int mlp_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
if (!sync_present) {
- // First nibble of a frame is a parity check of the first few nibbles.
+ /* The first nibble of a frame is a parity check of the 4-byte
+ * access unit header and all the 2- or 4-byte substream headers. */
// Only check when this isn't a sync frame - syncs have a checksum.
parity_bits = 0;
- for (i = 0; i <= mp->num_substreams; i++) {
+ for (i = -1; i < mp->num_substreams; i++) {
parity_bits ^= buf[p++];
parity_bits ^= buf[p++];
- if (i == 0 || buf[p-2] & 0x80) {
+ if (i < 0 || buf[p-2] & 0x80) {
parity_bits ^= buf[p++];
parity_bits ^= buf[p++];
}
goto lost_sync;
}
} else {
+ GetBitContext gb;
MLPHeaderInfo mh;
- if (ff_mlp_read_major_sync(avctx, &mh, buf + 4, buf_size - 4) < 0)
+ init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
+ if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
goto lost_sync;
-#ifdef CONFIG_AUDIO_NONSHORT
- avctx->bits_per_sample = mh.group1_bits;
- if (avctx->bits_per_sample > 16)
+ avctx->bits_per_raw_sample = mh.group1_bits;
+ if (avctx->bits_per_raw_sample > 16)
avctx->sample_fmt = SAMPLE_FMT_S32;
-#endif
+ else
+ avctx->sample_fmt = SAMPLE_FMT_S16;
avctx->sample_rate = mh.group1_samplerate;
avctx->frame_size = mh.access_unit_size;
lost_sync:
mp->in_sync = 0;
- return -1;
+ return 1;
}
AVCodecParser mlp_parser = {
- { CODEC_ID_MLP },
+ { CODEC_ID_MLP, CODEC_ID_TRUEHD },
sizeof(MLPParseContext),
- NULL,
+ mlp_init,
mlp_parse,
NULL,
};
projects / frescor / ffmpeg.git / blobdiff