[Ffmpeg-devel] TIFF LZW decoder (was: [PATCH] change gif demuxer to gif decoder)
Kostya
kostya.shishkov
Tue Oct 24 11:24:15 CEST 2006
On Tue, Oct 24, 2006 at 07:35:01AM +0300, Kostya wrote:
>
> As I understand, it may not need the wrapper, just two additional fields in
> structure: GetCode() pointer and dict_limit (when dictionary size reaches it,
> it should be expanded). I also tend to pass buffer and size to the structure
> instead of using bytestream.
>
> I intend to present this scheme to the end of week.
Here it is.
-------------- next part --------------
Index: libavcodec/lzw.c
===================================================================
--- libavcodec/lzw.c (revision 0)
+++ libavcodec/lzw.c (revision 0)
@@ -0,0 +1,216 @@
+/*
+ * LZW decoder
+ * Copyright (c) 2003 Fabrice Bellard.
+ * Copyright (c) 2006 Konstantin Shishkov.
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file lzw.c
+ * @brief LZW decoding routines
+ * @author Fabrice Bellard
+ * Modified for use in TIFF by Konstantin Shishkov
+ */
+
+#include "avcodec.h"
+#include "lzw.h"
+
+static const uint16_t mask[17] =
+{
+ 0x0000, 0x0001, 0x0003, 0x0007,
+ 0x000F, 0x001F, 0x003F, 0x007F,
+ 0x00FF, 0x01FF, 0x03FF, 0x07FF,
+ 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
+};
+
+static int get_code_gif(LZWState * s)
+{
+ int c, sizbuf;
+
+ while (s->bbits < s->cursize) {
+ if (!s->bs) {
+ sizbuf = *s->pbuf++;
+ s->bs = sizbuf;
+ if(!sizbuf) {
+ s->eob_reached = 1;
+ }
+ }
+ s->bbuf |= (*s->pbuf++) << s->bbits;
+ s->bbits += 8;
+ s->bs--;
+ }
+ c = s->bbuf & s->curmask;
+ s->bbuf >>= s->cursize;
+ s->bbits -= s->cursize;
+ return c;
+}
+
+static int get_code_tiff(LZWState * s)
+{
+ int c;
+
+ while (s->bbits < s->cursize) {
+ if (s->pbuf >= s->ebuf) {
+ s->eob_reached = 1;
+ }
+ s->bbuf = (s->bbuf << 8) | (*s->pbuf++);
+ s->bbits += 8;
+ }
+ c = (s->bbuf >> (s->bbits - s->cursize)) & s->curmask;
+ s->bbits -= s->cursize;
+ return c;
+}
+
+/**
+ * Initialize LZW decoder
+ * @param s LZW context
+ * @param csize initial code size in bits
+ * @param buf input data
+ * @param buf_size input data size
+ * @param mode decoder working mode - either GIF or TIFF
+ */
+int ff_lzw_decode_init(LZWState *s, int csize, uint8_t *buf, int buf_size, int mode)
+{
+ if(csize < 1 || csize > LZW_MAXBITS)
+ return -1;
+ /* read buffer */
+ s->eob_reached = 0;
+ s->pbuf = buf;
+ s->ebuf = s->pbuf + buf_size;
+ s->bbuf = 0;
+ s->bbits = 0;
+ s->bs = 0;
+
+ /* decoder */
+ s->codesize = csize;
+ s->cursize = s->codesize + 1;
+ s->curmask = mask[s->cursize];
+ s->top_slot = 1 << s->cursize;
+ s->clear_code = 1 << s->codesize;
+ s->end_code = s->clear_code + 1;
+ s->slot = s->newcodes = s->clear_code + 2;
+ s->oc = s->fc = 0;
+ s->sp = s->stack;
+
+ s->mode = mode;
+ switch(s->mode){
+ case FF_LZW_GIF:
+ s->get_code = get_code_gif;
+ s->top_slot2 = s->top_slot;
+ break;
+ case FF_LZW_TIFF:
+ s->get_code = get_code_tiff;
+ s->top_slot2 = s->top_slot - 1;
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * Decode given number of bytes
+ * NOTE: the algorithm here is inspired from the LZW GIF decoder
+ * written by Steven A. Bennett in 1987.
+ *
+ * @param s LZW context
+ * @param buf output buffer
+ * @param len number of bytes to decode
+ * @return number of bytes decoded
+ */
+int ff_lzw_decode(LZWState *s, uint8_t *buf, int len){
+ int l, c, code, oc, fc;
+ uint8_t *sp;
+
+ if (s->end_code < 0)
+ return 0;
+
+ l = len;
+ sp = s->sp;
+ oc = s->oc;
+ fc = s->fc;
+
+ while (sp > s->stack) {
+ *buf++ = *(--sp);
+ if ((--l) == 0)
+ goto the_end;
+ }
+
+ for (;;) {
+ c = s->get_code(s);
+ if (c == s->end_code) {
+ s->end_code = -1;
+ break;
+ } else if (c == s->clear_code) {
+ s->cursize = s->codesize + 1;
+ s->curmask = mask[s->cursize];
+ s->slot = s->newcodes;
+ s->top_slot = 1 << s->cursize;
+ s->top_slot2 = s->top_slot;
+ if(s->mode == FF_LZW_TIFF)
+ s->top_slot2--;
+ while ((c = s->get_code(s)) == s->clear_code);
+ if (c == s->end_code) {
+ s->end_code = -1;
+ break;
+ }
+ /* test error */
+ if (c >= s->slot)
+ c = 0;
+ fc = oc = c;
+ *buf++ = c;
+ if ((--l) == 0)
+ break;
+ } else {
+ code = c;
+ if (code >= s->slot) {
+ *sp++ = fc;
+ code = oc;
+ }
+ while (code >= s->newcodes) {
+ *sp++ = s->suffix[code];
+ code = s->prefix[code];
+ }
+ *sp++ = code;
+ if (s->slot < s->top_slot) {
+ s->suffix[s->slot] = fc = code;
+ s->prefix[s->slot++] = oc;
+ oc = c;
+ }
+ if (s->slot >= s->top_slot2) {
+ if (s->cursize < LZW_MAXBITS) {
+ s->top_slot <<= 1;
+ s->top_slot2 = s->top_slot;
+ if(s->mode == FF_LZW_TIFF)
+ s->top_slot2--;
+ s->curmask = mask[++s->cursize];
+ }
+ }
+ while (sp > s->stack) {
+ *buf++ = *(--sp);
+ if ((--l) == 0)
+ goto the_end;
+ }
+ }
+ }
+ the_end:
+ s->sp = sp;
+ s->oc = oc;
+ s->fc = fc;
+ return len - l;
+}
Index: libavcodec/lzw.h
===================================================================
--- libavcodec/lzw.h (revision 0)
+++ libavcodec/lzw.h (revision 0)
@@ -0,0 +1,77 @@
+/*
+ * LZW decoder
+ * Copyright (c) 2003 Fabrice Bellard.
+ * Copyright (c) 2006 Konstantin Shishkov.
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file lzw.h
+ * @brief LZW decoding routines
+ * @author Fabrice Bellard
+ * Modified for use in TIFF by Konstantin Shishkov
+ */
+
+#ifndef LZW_H
+#define LZW_H
+
+#define LZW_MAXBITS 12
+#define LZW_SIZTABLE (1<<LZW_MAXBITS)
+
+enum FF_LZW_MODES{
+ FF_LZW_GIF,
+ FF_LZW_TIFF
+};
+
+typedef struct LZWState {
+ int eob_reached;
+ uint8_t *pbuf, *ebuf;
+ int bbits;
+ unsigned int bbuf;
+
+ int mode; ///< Decoder mode
+ int cursize; ///< The current code size
+ int curmask;
+ int codesize;
+ int clear_code;
+ int end_code;
+ int newcodes; ///< First available code
+ int top_slot; ///< Highest code for current size
+ int top_slot2; ///< Highest possible code for current size (<=top_slot)
+ int slot; ///< Last read code
+ int fc, oc;
+ uint8_t *sp;
+ uint8_t stack[LZW_SIZTABLE];
+ uint8_t suffix[LZW_SIZTABLE];
+ uint16_t prefix[LZW_SIZTABLE];
+ int bs; ///< current buffer size for GIF
+
+ int (*get_code)(struct LZWState *s);
+} LZWState;
+
+int ff_lzw_decode_init(LZWState *s, int csize, uint8_t *buf, int buf_size, int mode);
+int ff_lzw_decode(LZWState *s, uint8_t *buf, int len);
+
+/* two macros for GIF */
+#define ff_lzw_cur_ptr(lzw) ((lzw)->pbuf)
+#define ff_lzw_decode_tail(lzw) { \
+ while(!(lzw)->eob_reached) \
+ (lzw)->get_code(lzw); \
+}
+
+#endif
Index: libavcodec/Makefile
===================================================================
--- libavcodec/Makefile (revision 6781)
+++ libavcodec/Makefile (working copy)
@@ -81,7 +81,7 @@
OBJS-$(CONFIG_FLIC_DECODER) += flicvideo.o
OBJS-$(CONFIG_FOURXM_DECODER) += 4xm.o
OBJS-$(CONFIG_FRAPS_DECODER) += fraps.o
-OBJS-$(CONFIG_GIF_DECODER) += gifdec.o
+OBJS-$(CONFIG_GIF_DECODER) += gifdec.o lzw.o
OBJS-$(CONFIG_H261_DECODER) += h261.o
OBJS-$(CONFIG_H261_ENCODER) += h261.o
OBJS-$(CONFIG_H264_DECODER) += h264.o
@@ -132,7 +132,7 @@
OBJS-$(CONFIG_SVQ3_DECODER) += h264.o
OBJS-$(CONFIG_TARGA_DECODER) += targa.o
OBJS-$(CONFIG_THEORA_DECODER) += vp3.o
-OBJS-$(CONFIG_TIFF_DECODER) += tiff.o
+OBJS-$(CONFIG_TIFF_DECODER) += tiff.o lzw.o
OBJS-$(CONFIG_TRUEMOTION1_DECODER) += truemotion1.o
OBJS-$(CONFIG_TRUEMOTION2_DECODER) += truemotion2.o
OBJS-$(CONFIG_TRUESPEECH_DECODER) += truespeech.o
Index: libavcodec/tiff.c
===================================================================
--- libavcodec/tiff.c (revision 6781)
+++ libavcodec/tiff.c (working copy)
@@ -23,6 +23,7 @@
#ifdef CONFIG_ZLIB
#include <zlib.h>
#endif
+#include "lzw.h"
/* abridged list of TIFF tags */
enum TiffTags{
@@ -74,6 +75,7 @@
uint8_t* stripdata;
uint8_t* stripsizes;
int stripsize, stripoff;
+ LZWState lzw;
} TiffContext;
static int tget_short(uint8_t **p, int le){
@@ -126,6 +128,12 @@
return 0;
}
#endif
+ if(s->compr == TIFF_LZW){
+ if(ff_lzw_decode_init(&s->lzw, 8, src, size, FF_LZW_TIFF) < 0){
+ av_log(s->avctx, AV_LOG_ERROR, "Error initializing LZW decoder\n");
+ return -1;
+ }
+ }
for(line = 0; line < lines; line++){
if(src - ssrc > size){
av_log(s->avctx, AV_LOG_ERROR, "Source data overread\n");
@@ -160,6 +168,13 @@
}
}
break;
+ case TIFF_LZW:
+ pixels = ff_lzw_decode(&s->lzw, dst, width);
+ if(pixels < width){
+ av_log(s->avctx, AV_LOG_ERROR, "Decoded only %i bytes of %i\n", pixels, width);
+ return -1;
+ }
+ break;
}
dst += stride;
}
@@ -247,6 +262,7 @@
switch(s->compr){
case TIFF_RAW:
case TIFF_PACKBITS:
+ case TIFF_LZW:
break;
case TIFF_DEFLATE:
case TIFF_ADOBE_DEFLATE:
@@ -256,9 +272,6 @@
av_log(s->avctx, AV_LOG_ERROR, "Deflate: ZLib not compiled in\n");
return -1;
#endif
- case TIFF_LZW:
- av_log(s->avctx, AV_LOG_ERROR, "LZW: not implemented yet\n");
- return -1;
case TIFF_G3:
av_log(s->avctx, AV_LOG_ERROR, "CCITT G3 compression is not supported\n");
return -1;
Index: libavcodec/gifdec.c
===================================================================
--- libavcodec/gifdec.c (revision 6781)
+++ libavcodec/gifdec.c (working copy)
@@ -24,10 +24,8 @@
#include "avcodec.h"
#include "bytestream.h"
+#include "lzw.h"
-#define MAXBITS 12
-#define SIZTABLE (1<<MAXBITS)
-
#define GCE_DISPOSAL_NONE 0
#define GCE_DISPOSAL_INPLACE 1
#define GCE_DISPOSAL_BACKGROUND 2
@@ -48,177 +46,17 @@
/* delay during which the frame is shown */
int gce_delay;
- /* LZW compatible decoder */
- uint8_t *bytestream;
- int eob_reached;
- uint8_t *pbuf, *ebuf;
- int bbits;
- unsigned int bbuf;
-
- int cursize; /* The current code size */
- int curmask;
- int codesize;
- int clear_code;
- int end_code;
- int newcodes; /* First available code */
- int top_slot; /* Highest code for current size */
- int slot; /* Last read code */
- int fc, oc;
- uint8_t *sp;
- uint8_t stack[SIZTABLE];
- uint8_t suffix[SIZTABLE];
- uint16_t prefix[SIZTABLE];
-
/* aux buffers */
uint8_t global_palette[256 * 3];
uint8_t local_palette[256 * 3];
- uint8_t buf[256];
+
+ uint8_t *bytestream;
+ LZWState lzw;
} GifState;
static const uint8_t gif87a_sig[6] = "GIF87a";
static const uint8_t gif89a_sig[6] = "GIF89a";
-static const uint16_t mask[17] =
-{
- 0x0000, 0x0001, 0x0003, 0x0007,
- 0x000F, 0x001F, 0x003F, 0x007F,
- 0x00FF, 0x01FF, 0x03FF, 0x07FF,
- 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
-};
-
-static void GLZWDecodeInit(GifState * s, int csize)
-{
- /* read buffer */
- s->eob_reached = 0;
- s->pbuf = s->buf;
- s->ebuf = s->buf;
- s->bbuf = 0;
- s->bbits = 0;
-
- /* decoder */
- s->codesize = csize;
- s->cursize = s->codesize + 1;
- s->curmask = mask[s->cursize];
- s->top_slot = 1 << s->cursize;
- s->clear_code = 1 << s->codesize;
- s->end_code = s->clear_code + 1;
- s->slot = s->newcodes = s->clear_code + 2;
- s->oc = s->fc = 0;
- s->sp = s->stack;
-}
-
-/* XXX: optimize */
-static inline int GetCode(GifState * s)
-{
- int c, sizbuf;
- uint8_t *ptr;
-
- while (s->bbits < s->cursize) {
- ptr = s->pbuf;
- if (ptr >= s->ebuf) {
- if (!s->eob_reached) {
- sizbuf = bytestream_get_byte(&s->bytestream);
- s->ebuf = s->buf + sizbuf;
- s->pbuf = s->buf;
- if (sizbuf > 0) {
- bytestream_get_buffer(&s->bytestream, s->buf, sizbuf);
- } else {
- s->eob_reached = 1;
- }
- }
- ptr = s->pbuf;
- }
- s->bbuf |= ptr[0] << s->bbits;
- ptr++;
- s->pbuf = ptr;
- s->bbits += 8;
- }
- c = s->bbuf & s->curmask;
- s->bbuf >>= s->cursize;
- s->bbits -= s->cursize;
- return c;
-}
-
-/* NOTE: the algorithm here is inspired from the LZW GIF decoder
- written by Steven A. Bennett in 1987. */
-/* return the number of byte decoded */
-static int GLZWDecode(GifState * s, uint8_t * buf, int len)
-{
- int l, c, code, oc, fc;
- uint8_t *sp;
-
- if (s->end_code < 0)
- return 0;
-
- l = len;
- sp = s->sp;
- oc = s->oc;
- fc = s->fc;
-
- while (sp > s->stack) {
- *buf++ = *(--sp);
- if ((--l) == 0)
- goto the_end;
- }
-
- for (;;) {
- c = GetCode(s);
- if (c == s->end_code) {
- s->end_code = -1;
- break;
- } else if (c == s->clear_code) {
- s->cursize = s->codesize + 1;
- s->curmask = mask[s->cursize];
- s->slot = s->newcodes;
- s->top_slot = 1 << s->cursize;
- while ((c = GetCode(s)) == s->clear_code);
- if (c == s->end_code) {
- s->end_code = -1;
- break;
- }
- /* test error */
- if (c >= s->slot)
- c = 0;
- fc = oc = c;
- *buf++ = c;
- if ((--l) == 0)
- break;
- } else {
- code = c;
- if (code >= s->slot) {
- *sp++ = fc;
- code = oc;
- }
- while (code >= s->newcodes) {
- *sp++ = s->suffix[code];
- code = s->prefix[code];
- }
- *sp++ = code;
- if (s->slot < s->top_slot) {
- s->suffix[s->slot] = fc = code;
- s->prefix[s->slot++] = oc;
- oc = c;
- }
- if (s->slot >= s->top_slot) {
- if (s->cursize < MAXBITS) {
- s->top_slot <<= 1;
- s->curmask = mask[++s->cursize];
- }
- }
- while (sp > s->stack) {
- *buf++ = *(--sp);
- if ((--l) == 0)
- goto the_end;
- }
- }
- }
- the_end:
- s->sp = sp;
- s->oc = oc;
- s->fc = fc;
- return len - l;
-}
-
static int gif_read_image(GifState *s)
{
int left, top, width, height, bits_per_pixel, code_size, flags;
@@ -267,7 +105,8 @@
/* now get the image data */
code_size = bytestream_get_byte(&s->bytestream);
- GLZWDecodeInit(s, code_size);
+ //TODO: add proper data size
+ ff_lzw_decode_init(&s->lzw, code_size, s->bytestream, 0, FF_LZW_GIF);
/* read all the image */
linesize = s->picture.linesize[0];
@@ -276,7 +115,7 @@
pass = 0;
y1 = 0;
for (y = 0; y < height; y++) {
- GLZWDecode(s, ptr, width);
+ ff_lzw_decode(&s->lzw, ptr, width);
if (is_interleaved) {
switch(pass) {
default:
@@ -314,8 +153,8 @@
av_free(line);
/* read the garbage data until end marker is found */
- while (!s->eob_reached)
- GetCode(s);
+ ff_lzw_decode_tail(&s->lzw);
+ s->bytestream = ff_lzw_cur_ptr(&s->lzw);
return 0;
}
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