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rtpdec_jpeg: Don't needlessly use a bitstream writer for the header 

Everything written with this bitstream writer is 8/16 bit units
(except for a pair of 4 bit values), so using a bitstream writer
isn't necessary.

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2012-09-11 12:44:25 +03:00
parent 43957fcc71
commit 20f325f320
1 changed files with 58 additions and 56 deletions
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114
libavformat/rtpdec_jpeg.c
View File

@ -23,6 +23,7 @@
#include "rtpdec_formats.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/mjpeg.h"
#include "libavcodec/bytestream.h"
/**
* RTP/JPEG specific private data.
@ -76,71 +77,75 @@ static void jpeg_free_context(PayloadContext *jpeg)
av_free(jpeg);
}
static int jpeg_create_huffman_table(PutBitContext *p, int table_class,
static int jpeg_create_huffman_table(PutByteContext *p, int table_class,
int table_id, const uint8_t *bits_table,
const uint8_t *value_table)
{
int i, n = 0;
put_bits(p, 4, table_class);
put_bits(p, 4, table_id);
bytestream2_put_byte(p, table_class << 4 | table_id);
for (i = 1; i <= 16; i++) {
n += bits_table[i];
put_bits(p, 8, bits_table[i]);
bytestream2_put_byte(p, bits_table[i]);
}
for (i = 0; i < n; i++) {
put_bits(p, 8, value_table[i]);
bytestream2_put_byte(p, value_table[i]);
}
return n + 17;
}
static void jpeg_put_marker(PutByteContext *pbc, int code)
{
bytestream2_put_byte(pbc, 0xff);
bytestream2_put_byte(pbc, code);
}
static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,
uint32_t h, const uint8_t *qtable, int nb_qtable)
{
PutBitContext pbc;
PutByteContext pbc;
uint8_t *dht_size_ptr;
int dht_size, i;
init_put_bits(&pbc, buf, size);
bytestream2_init_writer(&pbc, buf, size);
/* Convert from blocks to pixels. */
w <<= 3;
h <<= 3;
/* SOI */
put_marker(&pbc, SOI);
jpeg_put_marker(&pbc, SOI);
/* JFIF header */
put_marker(&pbc, APP0);
put_bits(&pbc, 16, 16);
avpriv_put_string(&pbc, "JFIF", 1);
put_bits(&pbc, 16, 0x0201);
put_bits(&pbc, 8, 0);
put_bits(&pbc, 16, 1);
put_bits(&pbc, 16, 1);
put_bits(&pbc, 8, 0);
put_bits(&pbc, 8, 0);
jpeg_put_marker(&pbc, APP0);
bytestream2_put_be16(&pbc, 16);
bytestream2_put_buffer(&pbc, "JFIF", 5);
bytestream2_put_be16(&pbc, 0x0201);
bytestream2_put_byte(&pbc, 0);
bytestream2_put_be16(&pbc, 1);
bytestream2_put_be16(&pbc, 1);
bytestream2_put_byte(&pbc, 0);
bytestream2_put_byte(&pbc, 0);
/* DQT */
put_marker(&pbc, DQT);
put_bits(&pbc, 16, 2 + nb_qtable * (1 + 64));
jpeg_put_marker(&pbc, DQT);
bytestream2_put_be16(&pbc, 2 + nb_qtable * (1 + 64));
for (i = 0; i < nb_qtable; i++) {
put_bits(&pbc, 8, i);
bytestream2_put_byte(&pbc, i);
/* Each table is an array of 64 values given in zig-zag
* order, identical to the format used in a JFIF DQT
* marker segment. */
avpriv_copy_bits(&pbc, qtable + 64 * i, 64 * 8);
bytestream2_put_buffer(&pbc, qtable + 64 * i, 64);
}
/* DHT */
put_marker(&pbc, DHT);
flush_put_bits(&pbc);
dht_size_ptr = put_bits_ptr(&pbc);
put_bits(&pbc, 16, 0);
jpeg_put_marker(&pbc, DHT);
dht_size_ptr = pbc.buffer;
bytestream2_put_be16(&pbc, 0);
dht_size = 2;
dht_size += jpeg_create_huffman_table(&pbc, 0, 0,avpriv_mjpeg_bits_dc_luminance,
@ -154,41 +159,38 @@ static int jpeg_create_header(uint8_t *buf, int size, uint32_t type, uint32_t w,
AV_WB16(dht_size_ptr, dht_size);
/* SOF0 */
put_marker(&pbc, SOF0);
put_bits(&pbc, 16, 17);
put_bits(&pbc, 8, 8);
put_bits(&pbc, 16, h);
put_bits(&pbc, 16, w);
put_bits(&pbc, 8, 3);
put_bits(&pbc, 8, 1);
put_bits(&pbc, 8, type ? 34 : 33);
put_bits(&pbc, 8, 0);
put_bits(&pbc, 8, 2);
put_bits(&pbc, 8, 17);
put_bits(&pbc, 8, nb_qtable == 2 ? 1 : 0);
put_bits(&pbc, 8, 3);
put_bits(&pbc, 8, 17);
put_bits(&pbc, 8, nb_qtable == 2 ? 1 : 0);
jpeg_put_marker(&pbc, SOF0);
bytestream2_put_be16(&pbc, 17);
bytestream2_put_byte(&pbc, 8);
bytestream2_put_be16(&pbc, h);
bytestream2_put_be16(&pbc, w);
bytestream2_put_byte(&pbc, 3);
bytestream2_put_byte(&pbc, 1);
bytestream2_put_byte(&pbc, type ? 34 : 33);
bytestream2_put_byte(&pbc, 0);
bytestream2_put_byte(&pbc, 2);
bytestream2_put_byte(&pbc, 17);
bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0);
bytestream2_put_byte(&pbc, 3);
bytestream2_put_byte(&pbc, 17);
bytestream2_put_byte(&pbc, nb_qtable == 2 ? 1 : 0);
/* SOS */
put_marker(&pbc, SOS);
put_bits(&pbc, 16, 12);
put_bits(&pbc, 8, 3);
put_bits(&pbc, 8, 1);
put_bits(&pbc, 8, 0);
put_bits(&pbc, 8, 2);
put_bits(&pbc, 8, 17);
put_bits(&pbc, 8, 3);
put_bits(&pbc, 8, 17);
put_bits(&pbc, 8, 0);
put_bits(&pbc, 8, 63);
put_bits(&pbc, 8, 0);
/* Fill the buffer. */
flush_put_bits(&pbc);
jpeg_put_marker(&pbc, SOS);
bytestream2_put_be16(&pbc, 12);
bytestream2_put_byte(&pbc, 3);
bytestream2_put_byte(&pbc, 1);
bytestream2_put_byte(&pbc, 0);
bytestream2_put_byte(&pbc, 2);
bytestream2_put_byte(&pbc, 17);
bytestream2_put_byte(&pbc, 3);
bytestream2_put_byte(&pbc, 17);
bytestream2_put_byte(&pbc, 0);
bytestream2_put_byte(&pbc, 63);
bytestream2_put_byte(&pbc, 0);
/* Return the length in bytes of the JPEG header. */
return put_bits_count(&pbc) / 8;
return bytestream2_tell_p(&pbc);
}
static void create_default_qtables(uint8_t *qtables, uint8_t q)