/*
- * H261 decoder
+ * H.261 decoder
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
* Copyright (c) 2004 Maarten Daniels
*
*/
#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
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
}
/* 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");
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);
}
}
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)
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;
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",
// 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;
}
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);
/* 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;
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 */
} 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);
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);
// 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);
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;
// 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;
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;
}
/* 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;
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
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
*/
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)
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 permutaton for reading a custom matrix
+ // we need the IDCT permutation for reading a custom matrix
ff_mpv_idct_init(s);
ret = h261_decode_picture_header(h);
projects / ffmpeg / blobdiff