4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * Modified 2003-2009 by Guido Vollbeding.
6 * This file is part of the Independent JPEG Group's software.
7 * For conditions of distribution and use, see the accompanying README file.
9 * This file contains routines to write JPEG datastream markers.
12 #define JPEG_INTERNALS
17 typedef enum { /* JPEG marker codes */
88 struct jpeg_marker_writer pub
; /* public fields */
90 unsigned int last_restart_interval
; /* last DRI value emitted; 0 after SOI */
93 typedef my_marker_writer
* my_marker_ptr
;
97 * Basic output routines.
99 * Note that we do not support suspension while writing a marker.
100 * Therefore, an application using suspension must ensure that there is
101 * enough buffer space for the initial markers (typ. 600-700 bytes) before
102 * calling jpeg_start_compress, and enough space to write the trailing EOI
103 * (a few bytes) before calling jpeg_finish_compress. Multipass compression
104 * modes are not supported at all with suspension, so those two are the only
105 * points where markers will be written.
109 emit_byte (j_compress_ptr cinfo
, int val
)
112 struct jpeg_destination_mgr
* dest
= cinfo
->dest
;
114 *(dest
->next_output_byte
)++ = (JOCTET
) val
;
115 if (--dest
->free_in_buffer
== 0) {
116 if (! (*dest
->empty_output_buffer
) (cinfo
))
117 ERREXIT(cinfo
, JERR_CANT_SUSPEND
);
123 emit_marker (j_compress_ptr cinfo
, JPEG_MARKER mark
)
124 /* Emit a marker code */
126 emit_byte(cinfo
, 0xFF);
127 emit_byte(cinfo
, (int) mark
);
132 emit_2bytes (j_compress_ptr cinfo
, int value
)
133 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
135 emit_byte(cinfo
, (value
>> 8) & 0xFF);
136 emit_byte(cinfo
, value
& 0xFF);
141 * Routines to write specific marker types.
145 emit_dqt (j_compress_ptr cinfo
, int index
)
146 /* Emit a DQT marker */
147 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
149 JQUANT_TBL
* qtbl
= cinfo
->quant_tbl_ptrs
[index
];
154 ERREXIT1(cinfo
, JERR_NO_QUANT_TABLE
, index
);
157 for (i
= 0; i
<= cinfo
->lim_Se
; i
++) {
158 if (qtbl
->quantval
[cinfo
->natural_order
[i
]] > 255)
162 if (! qtbl
->sent_table
) {
163 emit_marker(cinfo
, M_DQT
);
166 prec
? cinfo
->lim_Se
* 2 + 2 + 1 + 2 : cinfo
->lim_Se
+ 1 + 1 + 2);
168 emit_byte(cinfo
, index
+ (prec
<<4));
170 for (i
= 0; i
<= cinfo
->lim_Se
; i
++) {
171 /* The table entries must be emitted in zigzag order. */
172 unsigned int qval
= qtbl
->quantval
[cinfo
->natural_order
[i
]];
174 emit_byte(cinfo
, (int) (qval
>> 8));
175 emit_byte(cinfo
, (int) (qval
& 0xFF));
178 qtbl
->sent_table
= TRUE
;
186 emit_dht (j_compress_ptr cinfo
, int index
, boolean is_ac
)
187 /* Emit a DHT marker */
193 htbl
= cinfo
->ac_huff_tbl_ptrs
[index
];
194 index
+= 0x10; /* output index has AC bit set */
196 htbl
= cinfo
->dc_huff_tbl_ptrs
[index
];
200 ERREXIT1(cinfo
, JERR_NO_HUFF_TABLE
, index
);
202 if (! htbl
->sent_table
) {
203 emit_marker(cinfo
, M_DHT
);
206 for (i
= 1; i
<= 16; i
++)
207 length
+= htbl
->bits
[i
];
209 emit_2bytes(cinfo
, length
+ 2 + 1 + 16);
210 emit_byte(cinfo
, index
);
212 for (i
= 1; i
<= 16; i
++)
213 emit_byte(cinfo
, htbl
->bits
[i
]);
215 for (i
= 0; i
< length
; i
++)
216 emit_byte(cinfo
, htbl
->huffval
[i
]);
218 htbl
->sent_table
= TRUE
;
224 emit_dac (j_compress_ptr cinfo
)
225 /* Emit a DAC marker */
226 /* Since the useful info is so small, we want to emit all the tables in */
227 /* one DAC marker. Therefore this routine does its own scan of the table. */
229 #ifdef C_ARITH_CODING_SUPPORTED
230 char dc_in_use
[NUM_ARITH_TBLS
];
231 char ac_in_use
[NUM_ARITH_TBLS
];
233 jpeg_component_info
*compptr
;
235 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++)
236 dc_in_use
[i
] = ac_in_use
[i
] = 0;
238 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
239 compptr
= cinfo
->cur_comp_info
[i
];
240 /* DC needs no table for refinement scan */
241 if (cinfo
->Ss
== 0 && cinfo
->Ah
== 0)
242 dc_in_use
[compptr
->dc_tbl_no
] = 1;
243 /* AC needs no table when not present */
245 ac_in_use
[compptr
->ac_tbl_no
] = 1;
249 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++)
250 length
+= dc_in_use
[i
] + ac_in_use
[i
];
252 emit_marker(cinfo
, M_DAC
);
254 emit_2bytes(cinfo
, length
*2 + 2);
256 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++) {
259 emit_byte(cinfo
, cinfo
->arith_dc_L
[i
] + (cinfo
->arith_dc_U
[i
]<<4));
262 emit_byte(cinfo
, i
+ 0x10);
263 emit_byte(cinfo
, cinfo
->arith_ac_K
[i
]);
266 #endif /* C_ARITH_CODING_SUPPORTED */
271 emit_dri (j_compress_ptr cinfo
)
272 /* Emit a DRI marker */
274 emit_marker(cinfo
, M_DRI
);
276 emit_2bytes(cinfo
, 4); /* fixed length */
278 emit_2bytes(cinfo
, (int) cinfo
->restart_interval
);
283 emit_sof (j_compress_ptr cinfo
, JPEG_MARKER code
)
284 /* Emit a SOF marker */
287 jpeg_component_info
*compptr
;
289 emit_marker(cinfo
, code
);
291 emit_2bytes(cinfo
, 3 * cinfo
->num_components
+ 2 + 5 + 1); /* length */
293 /* Make sure image isn't bigger than SOF field can handle */
294 if ((long) cinfo
->jpeg_height
> 65535L ||
295 (long) cinfo
->jpeg_width
> 65535L)
296 ERREXIT1(cinfo
, JERR_IMAGE_TOO_BIG
, (unsigned int) 65535);
298 emit_byte(cinfo
, cinfo
->data_precision
);
299 emit_2bytes(cinfo
, (int) cinfo
->jpeg_height
);
300 emit_2bytes(cinfo
, (int) cinfo
->jpeg_width
);
302 emit_byte(cinfo
, cinfo
->num_components
);
304 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
306 emit_byte(cinfo
, compptr
->component_id
);
307 emit_byte(cinfo
, (compptr
->h_samp_factor
<< 4) + compptr
->v_samp_factor
);
308 emit_byte(cinfo
, compptr
->quant_tbl_no
);
314 emit_sos (j_compress_ptr cinfo
)
315 /* Emit a SOS marker */
318 jpeg_component_info
*compptr
;
320 emit_marker(cinfo
, M_SOS
);
322 emit_2bytes(cinfo
, 2 * cinfo
->comps_in_scan
+ 2 + 1 + 3); /* length */
324 emit_byte(cinfo
, cinfo
->comps_in_scan
);
326 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
327 compptr
= cinfo
->cur_comp_info
[i
];
328 emit_byte(cinfo
, compptr
->component_id
);
330 /* We emit 0 for unused field(s); this is recommended by the P&M text
331 * but does not seem to be specified in the standard.
334 /* DC needs no table for refinement scan */
335 td
= cinfo
->Ss
== 0 && cinfo
->Ah
== 0 ? compptr
->dc_tbl_no
: 0;
336 /* AC needs no table when not present */
337 ta
= cinfo
->Se
? compptr
->ac_tbl_no
: 0;
339 emit_byte(cinfo
, (td
<< 4) + ta
);
342 emit_byte(cinfo
, cinfo
->Ss
);
343 emit_byte(cinfo
, cinfo
->Se
);
344 emit_byte(cinfo
, (cinfo
->Ah
<< 4) + cinfo
->Al
);
349 emit_pseudo_sos (j_compress_ptr cinfo
)
350 /* Emit a pseudo SOS marker */
352 emit_marker(cinfo
, M_SOS
);
354 emit_2bytes(cinfo
, 2 + 1 + 3); /* length */
356 emit_byte(cinfo
, 0); /* Ns */
358 emit_byte(cinfo
, 0); /* Ss */
359 emit_byte(cinfo
, cinfo
->block_size
* cinfo
->block_size
- 1); /* Se */
360 emit_byte(cinfo
, 0); /* Ah/Al */
365 emit_jfif_app0 (j_compress_ptr cinfo
)
366 /* Emit a JFIF-compliant APP0 marker */
369 * Length of APP0 block (2 bytes)
370 * Block ID (4 bytes - ASCII "JFIF")
371 * Zero byte (1 byte to terminate the ID string)
372 * Version Major, Minor (2 bytes - major first)
373 * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
374 * Xdpu (2 bytes - dots per unit horizontal)
375 * Ydpu (2 bytes - dots per unit vertical)
376 * Thumbnail X size (1 byte)
377 * Thumbnail Y size (1 byte)
380 emit_marker(cinfo
, M_APP0
);
382 emit_2bytes(cinfo
, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
384 emit_byte(cinfo
, 0x4A); /* Identifier: ASCII "JFIF" */
385 emit_byte(cinfo
, 0x46);
386 emit_byte(cinfo
, 0x49);
387 emit_byte(cinfo
, 0x46);
389 emit_byte(cinfo
, cinfo
->JFIF_major_version
); /* Version fields */
390 emit_byte(cinfo
, cinfo
->JFIF_minor_version
);
391 emit_byte(cinfo
, cinfo
->density_unit
); /* Pixel size information */
392 emit_2bytes(cinfo
, (int) cinfo
->X_density
);
393 emit_2bytes(cinfo
, (int) cinfo
->Y_density
);
394 emit_byte(cinfo
, 0); /* No thumbnail image */
400 emit_adobe_app14 (j_compress_ptr cinfo
)
401 /* Emit an Adobe APP14 marker */
404 * Length of APP14 block (2 bytes)
405 * Block ID (5 bytes - ASCII "Adobe")
406 * Version Number (2 bytes - currently 100)
407 * Flags0 (2 bytes - currently 0)
408 * Flags1 (2 bytes - currently 0)
409 * Color transform (1 byte)
411 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
412 * now in circulation seem to use Version = 100, so that's what we write.
414 * We write the color transform byte as 1 if the JPEG color space is
415 * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
416 * whether the encoder performed a transformation, which is pretty useless.
419 emit_marker(cinfo
, M_APP14
);
421 emit_2bytes(cinfo
, 2 + 5 + 2 + 2 + 2 + 1); /* length */
423 emit_byte(cinfo
, 0x41); /* Identifier: ASCII "Adobe" */
424 emit_byte(cinfo
, 0x64);
425 emit_byte(cinfo
, 0x6F);
426 emit_byte(cinfo
, 0x62);
427 emit_byte(cinfo
, 0x65);
428 emit_2bytes(cinfo
, 100); /* Version */
429 emit_2bytes(cinfo
, 0); /* Flags0 */
430 emit_2bytes(cinfo
, 0); /* Flags1 */
431 switch (cinfo
->jpeg_color_space
) {
433 emit_byte(cinfo
, 1); /* Color transform = 1 */
436 emit_byte(cinfo
, 2); /* Color transform = 2 */
439 emit_byte(cinfo
, 0); /* Color transform = 0 */
446 * These routines allow writing an arbitrary marker with parameters.
447 * The only intended use is to emit COM or APPn markers after calling
448 * write_file_header and before calling write_frame_header.
449 * Other uses are not guaranteed to produce desirable results.
450 * Counting the parameter bytes properly is the caller's responsibility.
454 write_marker_header (j_compress_ptr cinfo
, int marker
, unsigned int datalen
)
455 /* Emit an arbitrary marker header */
457 if (datalen
> (unsigned int) 65533) /* safety check */
458 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
460 emit_marker(cinfo
, (JPEG_MARKER
) marker
);
462 emit_2bytes(cinfo
, (int) (datalen
+ 2)); /* total length */
466 write_marker_byte (j_compress_ptr cinfo
, int val
)
467 /* Emit one byte of marker parameters following write_marker_header */
469 emit_byte(cinfo
, val
);
474 * Write datastream header.
475 * This consists of an SOI and optional APPn markers.
476 * We recommend use of the JFIF marker, but not the Adobe marker,
477 * when using YCbCr or grayscale data. The JFIF marker should NOT
478 * be used for any other JPEG colorspace. The Adobe marker is helpful
479 * to distinguish RGB, CMYK, and YCCK colorspaces.
480 * Note that an application can write additional header markers after
481 * jpeg_start_compress returns.
485 write_file_header (j_compress_ptr cinfo
)
487 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
489 emit_marker(cinfo
, M_SOI
); /* first the SOI */
491 /* SOI is defined to reset restart interval to 0 */
492 marker
->last_restart_interval
= 0;
494 if (cinfo
->write_JFIF_header
) /* next an optional JFIF APP0 */
495 emit_jfif_app0(cinfo
);
496 if (cinfo
->write_Adobe_marker
) /* next an optional Adobe APP14 */
497 emit_adobe_app14(cinfo
);
502 * Write frame header.
503 * This consists of DQT and SOFn markers, and a conditional pseudo SOS marker.
504 * Note that we do not emit the SOF until we have emitted the DQT(s).
505 * This avoids compatibility problems with incorrect implementations that
506 * try to error-check the quant table numbers as soon as they see the SOF.
510 write_frame_header (j_compress_ptr cinfo
)
514 jpeg_component_info
*compptr
;
516 /* Emit DQT for each quantization table.
517 * Note that emit_dqt() suppresses any duplicate tables.
520 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
522 prec
+= emit_dqt(cinfo
, compptr
->quant_tbl_no
);
524 /* now prec is nonzero iff there are any 16-bit quant tables. */
526 /* Check for a non-baseline specification.
527 * Note we assume that Huffman table numbers won't be changed later.
529 if (cinfo
->arith_code
|| cinfo
->progressive_mode
||
530 cinfo
->data_precision
!= 8 || cinfo
->block_size
!= DCTSIZE
) {
534 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
536 if (compptr
->dc_tbl_no
> 1 || compptr
->ac_tbl_no
> 1)
539 if (prec
&& is_baseline
) {
541 /* If it's baseline except for quantizer size, warn the user */
542 TRACEMS(cinfo
, 0, JTRC_16BIT_TABLES
);
546 /* Emit the proper SOF marker */
547 if (cinfo
->arith_code
) {
548 if (cinfo
->progressive_mode
)
549 emit_sof(cinfo
, M_SOF10
); /* SOF code for progressive arithmetic */
551 emit_sof(cinfo
, M_SOF9
); /* SOF code for sequential arithmetic */
553 if (cinfo
->progressive_mode
)
554 emit_sof(cinfo
, M_SOF2
); /* SOF code for progressive Huffman */
555 else if (is_baseline
)
556 emit_sof(cinfo
, M_SOF0
); /* SOF code for baseline implementation */
558 emit_sof(cinfo
, M_SOF1
); /* SOF code for non-baseline Huffman file */
561 /* Check to emit pseudo SOS marker */
562 if (cinfo
->progressive_mode
&& cinfo
->block_size
!= DCTSIZE
)
563 emit_pseudo_sos(cinfo
);
569 * This consists of DHT or DAC markers, optional DRI, and SOS.
570 * Compressed data will be written following the SOS.
574 write_scan_header (j_compress_ptr cinfo
)
576 my_marker_ptr marker
= (my_marker_ptr
) cinfo
->marker
;
578 jpeg_component_info
*compptr
;
580 if (cinfo
->arith_code
) {
581 /* Emit arith conditioning info. We may have some duplication
582 * if the file has multiple scans, but it's so small it's hardly
583 * worth worrying about.
587 /* Emit Huffman tables.
588 * Note that emit_dht() suppresses any duplicate tables.
590 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
591 compptr
= cinfo
->cur_comp_info
[i
];
592 /* DC needs no table for refinement scan */
593 if (cinfo
->Ss
== 0 && cinfo
->Ah
== 0)
594 emit_dht(cinfo
, compptr
->dc_tbl_no
, FALSE
);
595 /* AC needs no table when not present */
597 emit_dht(cinfo
, compptr
->ac_tbl_no
, TRUE
);
601 /* Emit DRI if required --- note that DRI value could change for each scan.
602 * We avoid wasting space with unnecessary DRIs, however.
604 if (cinfo
->restart_interval
!= marker
->last_restart_interval
) {
606 marker
->last_restart_interval
= cinfo
->restart_interval
;
614 * Write datastream trailer.
618 write_file_trailer (j_compress_ptr cinfo
)
620 emit_marker(cinfo
, M_EOI
);
625 * Write an abbreviated table-specification datastream.
626 * This consists of SOI, DQT and DHT tables, and EOI.
627 * Any table that is defined and not marked sent_table = TRUE will be
628 * emitted. Note that all tables will be marked sent_table = TRUE at exit.
632 write_tables_only (j_compress_ptr cinfo
)
636 emit_marker(cinfo
, M_SOI
);
638 for (i
= 0; i
< NUM_QUANT_TBLS
; i
++) {
639 if (cinfo
->quant_tbl_ptrs
[i
] != NULL
)
640 (void) emit_dqt(cinfo
, i
);
643 if (! cinfo
->arith_code
) {
644 for (i
= 0; i
< NUM_HUFF_TBLS
; i
++) {
645 if (cinfo
->dc_huff_tbl_ptrs
[i
] != NULL
)
646 emit_dht(cinfo
, i
, FALSE
);
647 if (cinfo
->ac_huff_tbl_ptrs
[i
] != NULL
)
648 emit_dht(cinfo
, i
, TRUE
);
652 emit_marker(cinfo
, M_EOI
);
657 * Initialize the marker writer module.
661 jinit_marker_writer (j_compress_ptr cinfo
)
663 my_marker_ptr marker
;
665 /* Create the subobject */
666 marker
= (my_marker_ptr
)
667 (*cinfo
->mem
->alloc_small
) ((j_common_ptr
) cinfo
, JPOOL_IMAGE
,
668 SIZEOF(my_marker_writer
));
669 cinfo
->marker
= (struct jpeg_marker_writer
*) marker
;
670 /* Initialize method pointers */
671 marker
->pub
.write_file_header
= write_file_header
;
672 marker
->pub
.write_frame_header
= write_frame_header
;
673 marker
->pub
.write_scan_header
= write_scan_header
;
674 marker
->pub
.write_file_trailer
= write_file_trailer
;
675 marker
->pub
.write_tables_only
= write_tables_only
;
676 marker
->pub
.write_marker_header
= write_marker_header
;
677 marker
->pub
.write_marker_byte
= write_marker_byte
;
678 /* Initialize private state */
679 marker
->last_restart_interval
= 0;