highperfocused/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mlp: Split common code from parser and decoder to be used by encoder.

Browse Source 
Originally committed as revision 14733 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Ramiro Polla
2008-08-13 18:47:03 +00:00
parent e7327dbba7
commit ce15710f55
5 changed files with 247 additions and 180 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
libavcodec/mlp_parser.c
View File

@@ -30,6 +30,7 @@
#include "bitstream.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,
@@ -64,34 +65,6 @@ static int truehd_channels(int chanmap)
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
* are 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;
crc = av_crc(crc_2D, 0, buf, buf_size - 2);
crc ^= AV_RL16(buf + buf_size - 2);
return crc;
}
static int av_cold mlp_parse_init(AVCodecParserContext *s)
{
if (!crc_init) {
av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D));
crc_init = 1;
}
return 0;
}
/** 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.
@@ -110,7 +83,7 @@ int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
return -1;
}
checksum = mlp_checksum16(gb->buffer, 26);
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;
@@ -310,7 +283,7 @@ lost_sync:
AVCodecParser mlp_parser = {
{ CODEC_ID_MLP },
sizeof(MLPParseContext),
mlp_parse_init,
ff_mlp_init_crc2D,
mlp_parse,
NULL,
};