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h261dec: Convert to the new bitstream reader

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This commit is contained in:
Alexandra Hájková 2016-04-10 11:44:20 +02:00 committed by Diego Biurrun
parent 2b94ed12de
commit 2d72219554
3 changed files with 56 additions and 50 deletions
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92
libavcodec/h261dec.c
View File

@ -26,12 +26,14 @@
*/
#include "avcodec.h"
#include "bitstream.h"
#include "mpeg_er.h"
#include "mpegutils.h"
#include "mpegvideo.h"
#include "h263.h"
#include "h261.h"
#include "internal.h"
#include "vlc.h"
#define H261_MBA_VLC_BITS 9
#define H261_MTYPE_VLC_BITS 6
@ -103,18 +105,18 @@ static int h261_decode_gob_header(H261Context *h)
if (!h->gob_start_code_skipped) {
/* Check for GOB Start Code */
val = show_bits(&s->gb, 15);
val = bitstream_peek(&s->bc, 15);
if (val)
return -1;
/* We have a GBSC */
skip_bits(&s->gb, 16);
bitstream_skip(&s->bc, 16);
}
h->gob_start_code_skipped = 0;
h->gob_number = get_bits(&s->gb, 4); /* GN */
s->qscale = get_bits(&s->gb, 5); /* GQUANT */
h->gob_number = bitstream_read(&s->bc, 4); /* GN */
s->qscale = bitstream_read(&s->bc, 5); /* GQUANT */
/* Check if gob_number is valid */
if (s->mb_height == 18) { // CIF
@ -127,8 +129,8 @@ static int h261_decode_gob_header(H261Context *h)
}
/* GEI */
while (get_bits1(&s->gb) != 0)
skip_bits(&s->gb, 8);
while (bitstream_read_bit(&s->bc) != 0)
bitstream_skip(&s->bc, 8);
if (s->qscale == 0) {
av_log(s->avctx, AV_LOG_ERROR, "qscale has forbidden 0 value\n");
@ -160,27 +162,27 @@ static int h261_resync(H261Context *h)
if (ret >= 0)
return 0;
} else {
if (show_bits(&s->gb, 15) == 0) {
if (bitstream_peek(&s->bc, 15) == 0) {
ret = h261_decode_gob_header(h);
if (ret >= 0)
return 0;
}
// OK, it is not where it is supposed to be ...
s->gb = s->last_resync_gb;
align_get_bits(&s->gb);
left = get_bits_left(&s->gb);
s->bc = s->last_resync_bc;
bitstream_align(&s->bc);
left = bitstream_bits_left(&s->bc);
for (; left > 15 + 1 + 4 + 5; left -= 8) {
if (show_bits(&s->gb, 15) == 0) {
GetBitContext bak = s->gb;
if (bitstream_peek(&s->bc, 15) == 0) {
BitstreamContext bak = s->bc;
ret = h261_decode_gob_header(h);
if (ret >= 0)
return 0;
s->gb = bak;
s->bc = bak;
}
skip_bits(&s->gb, 8);
bitstream_skip(&s->bc, 8);
}
}
@ -228,9 +230,9 @@ static const int mvmap[17] = {
0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16
};
static int decode_mv_component(GetBitContext *gb, int v)
static int decode_mv_component(BitstreamContext *bc, int v)
{
int mv_diff = get_vlc2(gb, h261_mv_vlc.table, H261_MV_VLC_BITS, 2);
int mv_diff = bitstream_read_vlc(bc, h261_mv_vlc.table, H261_MV_VLC_BITS, 2);
/* check if mv_diff is valid */
if (mv_diff < 0)
@ -238,7 +240,7 @@ static int decode_mv_component(GetBitContext *gb, int v)
mv_diff = mvmap[mv_diff];
if (mv_diff && !get_bits1(gb))
if (mv_diff && !bitstream_read_bit(bc))
mv_diff = -mv_diff;
v += mv_diff;
@ -270,7 +272,7 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
scan_table = s->intra_scantable.permutated;
if (s->mb_intra) {
/* DC coef */
level = get_bits(&s->gb, 8);
level = bitstream_read(&s->bc, 8);
// 0 (00000000b) and -128 (10000000b) are FORBIDDEN
if ((level & 0x7F) == 0) {
av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n",
@ -288,10 +290,10 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
// EOB Not possible for first level when cbp is available (that's why the table is different)
// 0 1 1s
// * * 0*
int check = show_bits(&s->gb, 2);
int check = bitstream_peek(&s->bc, 2);
i = 0;
if (check & 0x2) {
skip_bits(&s->gb, 2);
bitstream_skip(&s->bc, 2);
block[0] = (check & 0x1) ? -1 : 1;
i = 1;
}
@ -303,7 +305,7 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
return 0;
}
for (;;) {
code = get_vlc2(&s->gb, rl->vlc.table, TCOEFF_VLC_BITS, 2);
code = bitstream_read_vlc(&s->bc, rl->vlc.table, TCOEFF_VLC_BITS, 2);
if (code < 0) {
av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n",
s->mb_x, s->mb_y);
@ -314,14 +316,14 @@ static int h261_decode_block(H261Context *h, int16_t *block, int n, int coded)
/* The remaining combinations of (run, level) are encoded with a
* 20-bit word consisting of 6 bits escape, 6 bits run and 8 bits
* level. */
run = get_bits(&s->gb, 6);
level = get_sbits(&s->gb, 8);
run = bitstream_read(&s->bc, 6);
level = bitstream_read_signed(&s->bc, 8);
} else if (code == 0) {
break;
} else {
run = rl->table_run[code];
level = rl->table_level[code];
if (get_bits1(&s->gb))
if (bitstream_read_bit(&s->bc))
level = -level;
}
i += run;
@ -346,8 +348,8 @@ static int h261_decode_mb(H261Context *h)
cbp = 63;
// Read mba
do {
h->mba_diff = get_vlc2(&s->gb, h261_mba_vlc.table,
H261_MBA_VLC_BITS, 2);
h->mba_diff = bitstream_read_vlc(&s->bc, h261_mba_vlc.table,
H261_MBA_VLC_BITS, 2);
/* Check for slice end */
/* NOTE: GOB can be empty (no MB data) or exist only of MBA_stuffing */
@ -358,7 +360,7 @@ static int h261_decode_mb(H261Context *h)
} while (h->mba_diff == MBA_STUFFING); // stuffing
if (h->mba_diff < 0) {
if (get_bits_left(&s->gb) <= 7)
if (bitstream_bits_left(&s->bc) <= 7)
return SLICE_END;
av_log(s->avctx, AV_LOG_ERROR, "illegal mba at %d %d\n", s->mb_x, s->mb_y);
@ -378,7 +380,7 @@ static int h261_decode_mb(H261Context *h)
ff_update_block_index(s);
// Read mtype
h->mtype = get_vlc2(&s->gb, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
h->mtype = bitstream_read_vlc(&s->bc, h261_mtype_vlc.table, H261_MTYPE_VLC_BITS, 2);
if (h->mtype < 0 || h->mtype >= FF_ARRAY_ELEMS(ff_h261_mtype_map)) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid mtype index %d\n",
h->mtype);
@ -388,7 +390,7 @@ static int h261_decode_mb(H261Context *h)
// Read mquant
if (IS_QUANT(h->mtype))
ff_set_qscale(s, get_bits(&s->gb, 5));
ff_set_qscale(s, bitstream_read(&s->bc, 5));
s->mb_intra = IS_INTRA4x4(h->mtype);
@ -408,8 +410,8 @@ static int h261_decode_mb(H261Context *h)
h->current_mv_y = 0;
}
h->current_mv_x = decode_mv_component(&s->gb, h->current_mv_x);
h->current_mv_y = decode_mv_component(&s->gb, h->current_mv_y);
h->current_mv_x = decode_mv_component(&s->bc, h->current_mv_x);
h->current_mv_y = decode_mv_component(&s->bc, h->current_mv_y);
} else {
h->current_mv_x = 0;
h->current_mv_y = 0;
@ -417,7 +419,7 @@ static int h261_decode_mb(H261Context *h)
// Read cbp
if (HAS_CBP(h->mtype))
cbp = get_vlc2(&s->gb, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 2) + 1;
cbp = bitstream_read_vlc(&s->bc, h261_cbp_vlc.table, H261_CBP_VLC_BITS, 2) + 1;
if (s->mb_intra) {
s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
@ -460,8 +462,8 @@ static int h261_decode_picture_header(H261Context *h)
int format, i;
uint32_t startcode = 0;
for (i = get_bits_left(&s->gb); i > 24; i -= 1) {
startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;
for (i = bitstream_bits_left(&s->bc); i > 24; i -= 1) {
startcode = ((startcode << 1) | bitstream_read(&s->bc, 1)) & 0x000FFFFF;
if (startcode == 0x10)
break;
@ -473,7 +475,7 @@ static int h261_decode_picture_header(H261Context *h)
}
/* temporal reference */
i = get_bits(&s->gb, 5); /* picture timestamp */
i = bitstream_read(&s->bc, 5); /* picture timestamp */
if (i < (s->picture_number & 31))
i += 32;
s->picture_number = (s->picture_number & ~31) + i;
@ -481,11 +483,11 @@ static int h261_decode_picture_header(H261Context *h)
s->avctx->framerate = (AVRational) { 30000, 1001 };
/* PTYPE starts here */
skip_bits1(&s->gb); /* split screen off */
skip_bits1(&s->gb); /* camera off */
skip_bits1(&s->gb); /* freeze picture release off */
bitstream_skip(&s->bc, 1); /* split screen off */
bitstream_skip(&s->bc, 1); /* camera off */
bitstream_skip(&s->bc, 1); /* freeze picture release off */
format = get_bits1(&s->gb);
format = bitstream_read_bit(&s->bc);
// only 2 formats possible
if (format == 0) { // QCIF
@ -502,12 +504,12 @@ static int h261_decode_picture_header(H261Context *h)
s->mb_num = s->mb_width * s->mb_height;
skip_bits1(&s->gb); /* still image mode off */
skip_bits1(&s->gb); /* Reserved */
bitstream_skip(&s->bc, 1); /* still image mode off */
bitstream_skip(&s->bc, 1); /* Reserved */
/* PEI */
while (get_bits1(&s->gb) != 0)
skip_bits(&s->gb, 8);
while (bitstream_read_bit(&s->bc) != 0)
bitstream_skip(&s->bc, 8);
/* H.261 has no I-frames, but if we pass AV_PICTURE_TYPE_I for the first
* frame, the codec crashes if it does not contain all I-blocks
@ -552,7 +554,7 @@ static int h261_decode_gob(H261Context *h)
*/
static int get_consumed_bytes(MpegEncContext *s, int buf_size)
{
int pos = get_bits_count(&s->gb) >> 3;
int pos = bitstream_tell(&s->bc) >> 3;
if (pos == 0)
pos = 1; // avoid infinite loops (i doubt that is needed but ...)
if (pos + 10 > buf_size)
@ -577,7 +579,7 @@ static int h261_decode_frame(AVCodecContext *avctx, void *data,
h->gob_start_code_skipped = 0;
retry:
init_get_bits(&s->gb, buf, buf_size * 8);
bitstream_init8(&s->bc, buf, buf_size);
if (!s->context_initialized)
// we need the IDCT permutation for reading a custom matrix

3
libavcodec/mpegvideo.h
View File

@ -31,6 +31,7 @@
#include <float.h>
#include "avcodec.h"
#include "bitstream.h"
#include "blockdsp.h"
#include "error_resilience.h"
#include "fdctdsp.h"
@ -344,6 +345,7 @@ typedef struct MpegEncContext {
int resync_mb_x; ///< x position of last resync marker
int resync_mb_y; ///< y position of last resync marker
GetBitContext last_resync_gb; ///< used to search for the next resync marker
BitstreamContext last_resync_bc; ///< used to search for the next resync marker
int mb_num_left; ///< number of MBs left in this video packet (for partitioned Slices only)
int next_p_frame_damaged; ///< set if the next p frame is damaged, to avoid showing trashed B-frames
@ -428,6 +430,7 @@ typedef struct MpegEncContext {
/* decompression specific */
GetBitContext gb;
BitstreamContext bc;
/* MPEG-1 specific */
int gop_picture_number; ///< index of the first picture of a GOP based on fake_pic_num & MPEG-1 specific

11
libavformat/h261dec.c
View File

@ -19,7 +19,8 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavcodec/get_bits.h"
#include "libavcodec/bitstream.h"
#include "avformat.h"
#include "rawdec.h"
@ -31,16 +32,16 @@ static int h261_probe(AVProbeData *p)
int invalid_psc=0;
int next_gn=0;
int src_fmt=0;
GetBitContext gb;
BitstreamContext bc;
init_get_bits(&gb, p->buf, p->buf_size*8);
bitstream_init(&bc, p->buf, p->buf_size * 8);
for(i=0; i<p->buf_size*8; i++){
if ((code & 0x01ff0000) || !(code & 0xff00)) {
code = (code<<8) + get_bits(&gb, 8);
code = (code << 8) + bitstream_read(&bc, 8);
i += 7;
} else
code = (code<<1) + get_bits1(&gb);
code = (code << 1) + bitstream_read_bit(&bc);
if ((code & 0xffff0000) == 0x10000) {
int gn= (code>>12)&0xf;
if(!gn)