[deb_ffmpeg.git] / ffmpeg / libavcodec / vc1_parser.c

/*
 * VC-1 and WMV3 parser
 * Copyright (c) 2006-2007 Konstantin Shishkov
 * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
 *
 * 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
 * VC-1 and WMV3 parser
 */

#include "libavutil/attributes.h"
#include "parser.h"
#include "vc1.h"
#include "get_bits.h"

/** The maximum number of bytes of a sequence, entry point or
 *  frame header whose values we pay any attention to */
#define UNESCAPED_THRESHOLD 37

/** The maximum number of bytes of a sequence, entry point or
 *  frame header which must be valid memory (because they are
 *  used to update the bitstream cache in skip_bits() calls)
 */
#define UNESCAPED_LIMIT 144

typedef enum {
    NO_MATCH,
    ONE_ZERO,
    TWO_ZEROS,
    ONE
} VC1ParseSearchState;

typedef struct {
    ParseContext pc;
    VC1Context v;
    uint8_t prev_start_code;
    size_t bytes_to_skip;
    uint8_t unesc_buffer[UNESCAPED_LIMIT];
    size_t unesc_index;
    VC1ParseSearchState search_state;
} VC1ParseContext;

static void vc1_extract_header(AVCodecParserContext *s, AVCodecContext *avctx,
                               const uint8_t *buf, int buf_size)
{
    /* Parse the header we just finished unescaping */
    VC1ParseContext *vpc = s->priv_data;
    GetBitContext gb;
    int ret;
    vpc->v.s.avctx = avctx;
    vpc->v.parse_only = 1;
    init_get_bits(&gb, buf, buf_size * 8);
    switch (vpc->prev_start_code) {
    case VC1_CODE_SEQHDR & 0xFF:
        ff_vc1_decode_sequence_header(avctx, &vpc->v, &gb);
        break;
    case VC1_CODE_ENTRYPOINT & 0xFF:
        ff_vc1_decode_entry_point(avctx, &vpc->v, &gb);
        break;
    case VC1_CODE_FRAME & 0xFF:
        if(vpc->v.profile < PROFILE_ADVANCED)
            ret = ff_vc1_parse_frame_header    (&vpc->v, &gb);
        else
            ret = ff_vc1_parse_frame_header_adv(&vpc->v, &gb);

        if (ret < 0)
            break;

        /* keep AV_PICTURE_TYPE_BI internal to VC1 */
        if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
            s->pict_type = AV_PICTURE_TYPE_B;
        else
            s->pict_type = vpc->v.s.pict_type;

        if (avctx->ticks_per_frame > 1){
            // process pulldown flags
            s->repeat_pict = 1;
            // Pulldown flags are only valid when 'broadcast' has been set.
            // So ticks_per_frame will be 2
            if (vpc->v.rff){
                // repeat field
                s->repeat_pict = 2;
            }else if (vpc->v.rptfrm){
                // repeat frames
                s->repeat_pict = vpc->v.rptfrm * 2 + 1;
            }
        }else{
            s->repeat_pict = 0;
        }

        if (vpc->v.broadcast && vpc->v.interlace && !vpc->v.psf)
            s->field_order = vpc->v.tff ? AV_FIELD_TT : AV_FIELD_BB;
        else
            s->field_order = AV_FIELD_PROGRESSIVE;

        break;
    }
    if (avctx->framerate.num)
        avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
}

static int vc1_parse(AVCodecParserContext *s,
                           AVCodecContext *avctx,
                           const uint8_t **poutbuf, int *poutbuf_size,
                           const uint8_t *buf, int buf_size)
{
    /* Here we do the searching for frame boundaries and headers at
     * the same time. Only a minimal amount at the start of each
     * header is unescaped. */
    VC1ParseContext *vpc = s->priv_data;
    int pic_found = vpc->pc.frame_start_found;
    uint8_t *unesc_buffer = vpc->unesc_buffer;
    size_t unesc_index = vpc->unesc_index;
    VC1ParseSearchState search_state = vpc->search_state;
    int start_code_found = 0;
    int next = END_NOT_FOUND;
    int i = vpc->bytes_to_skip;

    if (pic_found && buf_size == 0) {
        /* EOF considered as end of frame */
        memset(unesc_buffer + unesc_index, 0, UNESCAPED_THRESHOLD - unesc_index);
        vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
        next = 0;
    }
    while (i < buf_size) {
        uint8_t b;
        start_code_found = 0;
        while (i < buf_size && unesc_index < UNESCAPED_THRESHOLD) {
            b = buf[i++];
            unesc_buffer[unesc_index++] = b;
            if (search_state <= ONE_ZERO)
                search_state = b ? NO_MATCH : search_state + 1;
            else if (search_state == TWO_ZEROS) {
                if (b == 1)
                    search_state = ONE;
                else if (b > 1) {
                    if (b == 3)
                        unesc_index--; // swallow emulation prevention byte
                    search_state = NO_MATCH;
                }
            }
            else { // search_state == ONE
                // Header unescaping terminates early due to detection of next start code
                search_state = NO_MATCH;
                start_code_found = 1;
                break;
            }
        }
        if ((s->flags & PARSER_FLAG_COMPLETE_FRAMES) &&
                unesc_index >= UNESCAPED_THRESHOLD &&
                vpc->prev_start_code == (VC1_CODE_FRAME & 0xFF))
        {
            // No need to keep scanning the rest of the buffer for
            // start codes if we know it contains a complete frame and
            // we've already unescaped all we need of the frame header
            vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
            break;
        }
        if (unesc_index >= UNESCAPED_THRESHOLD && !start_code_found) {
            while (i < buf_size) {
                if (search_state == NO_MATCH) {
                    i += vpc->v.vc1dsp.startcode_find_candidate(buf + i, buf_size - i);
                    if (i < buf_size) {
                        search_state = ONE_ZERO;
                    }
                    i++;
                } else {
                    b = buf[i++];
                    if (search_state == ONE_ZERO)
                        search_state = b ? NO_MATCH : TWO_ZEROS;
                    else if (search_state == TWO_ZEROS) {
                        if (b >= 1)
                            search_state = b == 1 ? ONE : NO_MATCH;
                    }
                    else { // search_state == ONE
                        search_state = NO_MATCH;
                        start_code_found = 1;
                        break;
                    }
                }
            }
        }
        if (start_code_found) {
            vc1_extract_header(s, avctx, unesc_buffer, unesc_index);

            vpc->prev_start_code = b;
            unesc_index = 0;

            if (!(s->flags & PARSER_FLAG_COMPLETE_FRAMES)) {
                if (!pic_found && (b == (VC1_CODE_FRAME & 0xFF) || b == (VC1_CODE_FIELD & 0xFF))) {
                    pic_found = 1;
                }
                else if (pic_found && b != (VC1_CODE_FIELD & 0xFF) && b != (VC1_CODE_SLICE & 0xFF)) {
                    next = i - 4;
                    pic_found = b == (VC1_CODE_FRAME & 0xFF);
                    break;
                }
            }
        }
    }

    vpc->pc.frame_start_found = pic_found;
    vpc->unesc_index = unesc_index;
    vpc->search_state = search_state;

    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
        next = buf_size;
    } else {
        if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
            vpc->bytes_to_skip = 0;
            *poutbuf = NULL;
            *poutbuf_size = 0;
            return buf_size;
        }
    }

    /* If we return with a valid pointer to a combined frame buffer
     * then on the next call then we'll have been unhelpfully rewound
     * by up to 4 bytes (depending upon whether the start code
     * overlapped the input buffer, and if so by how much). We don't
     * want this: it will either cause spurious second detections of
     * the start code we've already seen, or cause extra bytes to be
     * inserted at the start of the unescaped buffer. */
    vpc->bytes_to_skip = 4;
    if (next < 0 && next != END_NOT_FOUND)
        vpc->bytes_to_skip += next;

    *poutbuf = buf;
    *poutbuf_size = buf_size;
    return next;
}

static int vc1_split(AVCodecContext *avctx,
                           const uint8_t *buf, int buf_size)
{
    int i;
    uint32_t state= -1;
    int charged=0;

    for(i=0; i<buf_size; i++){
        state= (state<<8) | buf[i];
        if(IS_MARKER(state)){
            if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
                charged=1;
            }else if(charged){
                return i-3;
            }
        }
    }
    return 0;
}

static av_cold int vc1_parse_init(AVCodecParserContext *s)
{
    VC1ParseContext *vpc = s->priv_data;
    vpc->v.s.slice_context_count = 1;
    vpc->v.first_pic_header_flag = 1;
    vpc->prev_start_code = 0;
    vpc->bytes_to_skip = 0;
    vpc->unesc_index = 0;
    vpc->search_state = NO_MATCH;
    return ff_vc1_init_common(&vpc->v);
}

AVCodecParser ff_vc1_parser = {
    .codec_ids      = { AV_CODEC_ID_VC1 },
    .priv_data_size = sizeof(VC1ParseContext),
    .parser_init    = vc1_parse_init,
    .parser_parse   = vc1_parse,
    .parser_close   = ff_parse_close,
    .split          = vc1_split,
};
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* VC-1 and WMV3 parser
	3	* Copyright (c) 2006-2007 Konstantin Shishkov
	4	* Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
	5	*
	6	* This file is part of FFmpeg.
	7	*
	8	* FFmpeg is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; either
	11	* version 2.1 of the License, or (at your option) any later version.
	12	*
	13	* FFmpeg is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with FFmpeg; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
	23	/**
	24	* @file
	25	* VC-1 and WMV3 parser
	26	*/
	27
	28	#include "libavutil/attributes.h"
	29	#include "parser.h"
	30	#include "vc1.h"
	31	#include "get_bits.h"
	32
	33	/** The maximum number of bytes of a sequence, entry point or
	34	* frame header whose values we pay any attention to */
	35	#define UNESCAPED_THRESHOLD 37
	36
	37	/** The maximum number of bytes of a sequence, entry point or
	38	* frame header which must be valid memory (because they are
	39	* used to update the bitstream cache in skip_bits() calls)
	40	*/
	41	#define UNESCAPED_LIMIT 144
	42
	43	typedef enum {
	44	NO_MATCH,
	45	ONE_ZERO,
	46	TWO_ZEROS,
	47	ONE
	48	} VC1ParseSearchState;
	49
	50	typedef struct {
	51	ParseContext pc;
	52	VC1Context v;
	53	uint8_t prev_start_code;
	54	size_t bytes_to_skip;
	55	uint8_t unesc_buffer[UNESCAPED_LIMIT];
	56	size_t unesc_index;
	57	VC1ParseSearchState search_state;
	58	} VC1ParseContext;
	59
	60	static void vc1_extract_header(AVCodecParserContext s, AVCodecContext avctx,
	61	const uint8_t *buf, int buf_size)
	62	{
	63	/* Parse the header we just finished unescaping */
	64	VC1ParseContext *vpc = s->priv_data;
65	GetBitContext gb;
66	int ret;
67	vpc->v.s.avctx = avctx;
68	vpc->v.parse_only = 1;
69	init_get_bits(&gb, buf, buf_size * 8);
70	switch (vpc->prev_start_code) {
71	case VC1_CODE_SEQHDR & 0xFF:
72	ff_vc1_decode_sequence_header(avctx, &vpc->v, &gb);
73	break;
74	case VC1_CODE_ENTRYPOINT & 0xFF:
75	ff_vc1_decode_entry_point(avctx, &vpc->v, &gb);
76	break;
77	case VC1_CODE_FRAME & 0xFF:
78	if(vpc->v.profile < PROFILE_ADVANCED)
79	ret = ff_vc1_parse_frame_header (&vpc->v, &gb);
80	else
81	ret = ff_vc1_parse_frame_header_adv(&vpc->v, &gb);
82
83	if (ret < 0)
84	break;
85
86	/* keep AV_PICTURE_TYPE_BI internal to VC1 */
87	if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
88	s->pict_type = AV_PICTURE_TYPE_B;
89	else
90	s->pict_type = vpc->v.s.pict_type;
91
92	if (avctx->ticks_per_frame > 1){
93	// process pulldown flags
94	s->repeat_pict = 1;
95	// Pulldown flags are only valid when 'broadcast' has been set.
96	// So ticks_per_frame will be 2
97	if (vpc->v.rff){
98	// repeat field
99	s->repeat_pict = 2;
100	}else if (vpc->v.rptfrm){
101	// repeat frames
102	s->repeat_pict = vpc->v.rptfrm * 2 + 1;
103	}
104	}else{
105	s->repeat_pict = 0;
106	}
107
108	if (vpc->v.broadcast && vpc->v.interlace && !vpc->v.psf)
109	s->field_order = vpc->v.tff ? AV_FIELD_TT : AV_FIELD_BB;
110	else
111	s->field_order = AV_FIELD_PROGRESSIVE;
112
113	break;
114	}
f6fa7814 DM	115	if (avctx->framerate.num)
f6fa7814 DM	116	avctx->time_base = av_inv_q(av_mul_q(avctx->framerate, (AVRational){avctx->ticks_per_frame, 1}));
2ba45a60 DM	117	}
	118
	119	static int vc1_parse(AVCodecParserContext *s,
	120	AVCodecContext *avctx,
	121	const uint8_t *poutbuf, int poutbuf_size,
	122	const uint8_t *buf, int buf_size)
	123	{
	124	/* Here we do the searching for frame boundaries and headers at
	125	* the same time. Only a minimal amount at the start of each
	126	* header is unescaped. */
	127	VC1ParseContext *vpc = s->priv_data;
	128	int pic_found = vpc->pc.frame_start_found;
	129	uint8_t *unesc_buffer = vpc->unesc_buffer;
	130	size_t unesc_index = vpc->unesc_index;
	131	VC1ParseSearchState search_state = vpc->search_state;
	132	int start_code_found = 0;
	133	int next = END_NOT_FOUND;
	134	int i = vpc->bytes_to_skip;
	135
	136	if (pic_found && buf_size == 0) {
	137	/* EOF considered as end of frame */
	138	memset(unesc_buffer + unesc_index, 0, UNESCAPED_THRESHOLD - unesc_index);
	139	vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
	140	next = 0;
	141	}
	142	while (i < buf_size) {
	143	uint8_t b;
	144	start_code_found = 0;
	145	while (i < buf_size && unesc_index < UNESCAPED_THRESHOLD) {
	146	b = buf[i++];
	147	unesc_buffer[unesc_index++] = b;
	148	if (search_state <= ONE_ZERO)
	149	search_state = b ? NO_MATCH : search_state + 1;
	150	else if (search_state == TWO_ZEROS) {
	151	if (b == 1)
	152	search_state = ONE;
	153	else if (b > 1) {
	154	if (b == 3)
	155	unesc_index--; // swallow emulation prevention byte
	156	search_state = NO_MATCH;
	157	}
	158	}
	159	else { // search_state == ONE
	160	// Header unescaping terminates early due to detection of next start code
	161	search_state = NO_MATCH;
	162	start_code_found = 1;
	163	break;
	164	}
	165	}
	166	if ((s->flags & PARSER_FLAG_COMPLETE_FRAMES) &&
	167	unesc_index >= UNESCAPED_THRESHOLD &&
	168	vpc->prev_start_code == (VC1_CODE_FRAME & 0xFF))
	169	{
	170	// No need to keep scanning the rest of the buffer for
	171	// start codes if we know it contains a complete frame and
	172	// we've already unescaped all we need of the frame header
	173	vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
	174	break;
	175	}
	176	if (unesc_index >= UNESCAPED_THRESHOLD && !start_code_found) {
	177	while (i < buf_size) {
	178	if (search_state == NO_MATCH) {
	179	i += vpc->v.vc1dsp.startcode_find_candidate(buf + i, buf_size - i);
	180	if (i < buf_size) {
181	search_state = ONE_ZERO;
182	}
183	i++;
184	} else {
185	b = buf[i++];
186	if (search_state == ONE_ZERO)
187	search_state = b ? NO_MATCH : TWO_ZEROS;
188	else if (search_state == TWO_ZEROS) {
189	if (b >= 1)
190	search_state = b == 1 ? ONE : NO_MATCH;
191	}
192	else { // search_state == ONE
193	search_state = NO_MATCH;
194	start_code_found = 1;
195	break;
196	}
197	}
198	}
199	}
200	if (start_code_found) {
201	vc1_extract_header(s, avctx, unesc_buffer, unesc_index);
202
203	vpc->prev_start_code = b;
204	unesc_index = 0;
205
206	if (!(s->flags & PARSER_FLAG_COMPLETE_FRAMES)) {
207	if (!pic_found && (b == (VC1_CODE_FRAME & 0xFF) \|\| b == (VC1_CODE_FIELD & 0xFF))) {
208	pic_found = 1;
209	}
210	else if (pic_found && b != (VC1_CODE_FIELD & 0xFF) && b != (VC1_CODE_SLICE & 0xFF)) {
211	next = i - 4;
212	pic_found = b == (VC1_CODE_FRAME & 0xFF);
213	break;
214	}
215	}
216	}
217	}
218
219	vpc->pc.frame_start_found = pic_found;
220	vpc->unesc_index = unesc_index;
221	vpc->search_state = search_state;
222
223	if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
224	next = buf_size;
225	} else {
226	if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
227	vpc->bytes_to_skip = 0;
228	*poutbuf = NULL;
229	*poutbuf_size = 0;
230	return buf_size;
231	}
232	}
233
234	/* If we return with a valid pointer to a combined frame buffer
235	* then on the next call then we'll have been unhelpfully rewound
236	* by up to 4 bytes (depending upon whether the start code
237	* overlapped the input buffer, and if so by how much). We don't
238	* want this: it will either cause spurious second detections of
239	* the start code we've already seen, or cause extra bytes to be
240	* inserted at the start of the unescaped buffer. */
241	vpc->bytes_to_skip = 4;
242	if (next < 0 && next != END_NOT_FOUND)
243	vpc->bytes_to_skip += next;
244
245	*poutbuf = buf;
246	*poutbuf_size = buf_size;
247	return next;
248	}
249
250	static int vc1_split(AVCodecContext *avctx,
251	const uint8_t *buf, int buf_size)
252	{
253	int i;
254	uint32_t state= -1;
255	int charged=0;
256
257	for(i=0; i<buf_size; i++){
258	state= (state<<8) \| buf[i];
259	if(IS_MARKER(state)){
260	if(state == VC1_CODE_SEQHDR \|\| state == VC1_CODE_ENTRYPOINT){
261	charged=1;
262	}else if(charged){
263	return i-3;
264	}
265	}
266	}
267	return 0;
268	}
269
270	static av_cold int vc1_parse_init(AVCodecParserContext *s)
271	{
272	VC1ParseContext *vpc = s->priv_data;
273	vpc->v.s.slice_context_count = 1;
274	vpc->v.first_pic_header_flag = 1;
275	vpc->prev_start_code = 0;
276	vpc->bytes_to_skip = 0;
277	vpc->unesc_index = 0;
278	vpc->search_state = NO_MATCH;
279	return ff_vc1_init_common(&vpc->v);
280	}
281
282	AVCodecParser ff_vc1_parser = {
283	.codec_ids = { AV_CODEC_ID_VC1 },
284	.priv_data_size = sizeof(VC1ParseContext),
285	.parser_init = vc1_parse_init,
286	.parser_parse = vc1_parse,
287	.parser_close = ff_parse_close,
288	.split = vc1_split,
289	};