yading@10: /*
yading@10:  * DCA parser
yading@10:  * Copyright (C) 2004 Gildas Bazin
yading@10:  * Copyright (C) 2004 Benjamin Zores
yading@10:  * Copyright (C) 2006 Benjamin Larsson
yading@10:  * Copyright (C) 2007 Konstantin Shishkov
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "parser.h"
yading@10: #include "dca.h"
yading@10: #include "get_bits.h"
yading@10: 
yading@10: typedef struct DCAParseContext {
yading@10:     ParseContext pc;
yading@10:     uint32_t lastmarker;
yading@10:     int size;
yading@10:     int framesize;
yading@10:     int hd_pos;
yading@10: } DCAParseContext;
yading@10: 
yading@10: #define IS_MARKER(state, i, buf, buf_size) \
yading@10:  ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \
yading@10:  || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \
yading@10:  || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE || state == DCA_HD_MARKER)
yading@10: 
yading@10: /**
yading@10:  * Find the end of the current frame in the bitstream.
yading@10:  * @return the position of the first byte of the next frame, or -1
yading@10:  */
yading@10: static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,
yading@10:                               int buf_size)
yading@10: {
yading@10:     int start_found, i;
yading@10:     uint32_t state;
yading@10:     ParseContext *pc = &pc1->pc;
yading@10: 
yading@10:     start_found = pc->frame_start_found;
yading@10:     state = pc->state;
yading@10: 
yading@10:     i = 0;
yading@10:     if (!start_found) {
yading@10:         for (i = 0; i < buf_size; i++) {
yading@10:             state = (state << 8) | buf[i];
yading@10:             if (IS_MARKER(state, i, buf, buf_size)) {
yading@10:                 if (!pc1->lastmarker || state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER) {
yading@10:                     start_found = 1;
yading@10:                     pc1->lastmarker = state;
yading@10:                     break;
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     if (start_found) {
yading@10:         for (; i < buf_size; i++) {
yading@10:             pc1->size++;
yading@10:             state = (state << 8) | buf[i];
yading@10:             if (state == DCA_HD_MARKER && !pc1->hd_pos)
yading@10:                 pc1->hd_pos = pc1->size;
yading@10:             if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) {
yading@10:                 if(pc1->framesize > pc1->size)
yading@10:                     continue;
yading@10:                 // We have to check that we really read a full frame here, and that it isn't a pure HD frame, because their size is not constant.
yading@10:                 if(!pc1->framesize && state == pc1->lastmarker && state != DCA_HD_MARKER){
yading@10:                     pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size;
yading@10:                 }
yading@10:                 pc->frame_start_found = 0;
yading@10:                 pc->state = -1;
yading@10:                 pc1->size = 0;
yading@10:                 return i - 3;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     pc->frame_start_found = start_found;
yading@10:     pc->state = state;
yading@10:     return END_NOT_FOUND;
yading@10: }
yading@10: 
yading@10: static av_cold int dca_parse_init(AVCodecParserContext * s)
yading@10: {
yading@10:     DCAParseContext *pc1 = s->priv_data;
yading@10: 
yading@10:     pc1->lastmarker = 0;
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,
yading@10:                             int *sample_rate)
yading@10: {
yading@10:     GetBitContext gb;
yading@10:     uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
yading@10:     int ret, sample_blocks, sr_code;
yading@10: 
yading@10:     if (buf_size < 12)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     init_get_bits(&gb, hdr, 96);
yading@10: 
yading@10:     skip_bits_long(&gb, 39);
yading@10:     sample_blocks = get_bits(&gb, 7) + 1;
yading@10:     if (sample_blocks < 8)
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     *duration = 256 * (sample_blocks / 8);
yading@10: 
yading@10:     skip_bits(&gb, 20);
yading@10:     sr_code = get_bits(&gb, 4);
yading@10:     *sample_rate = avpriv_dca_sample_rates[sr_code];
yading@10:     if (*sample_rate == 0)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int dca_parse(AVCodecParserContext * s,
yading@10:                      AVCodecContext * avctx,
yading@10:                      const uint8_t ** poutbuf, int *poutbuf_size,
yading@10:                      const uint8_t * buf, int buf_size)
yading@10: {
yading@10:     DCAParseContext *pc1 = s->priv_data;
yading@10:     ParseContext *pc = &pc1->pc;
yading@10:     int next, duration, sample_rate;
yading@10: 
yading@10:     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
yading@10:         next = buf_size;
yading@10:     } else {
yading@10:         next = dca_find_frame_end(pc1, buf, buf_size);
yading@10: 
yading@10:         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
yading@10:             *poutbuf = NULL;
yading@10:             *poutbuf_size = 0;
yading@10:             return buf_size;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     /* read the duration and sample rate from the frame header */
yading@10:     if (!dca_parse_params(buf, buf_size, &duration, &sample_rate)) {
yading@10:         s->duration = duration;
yading@10:         avctx->sample_rate = sample_rate;
yading@10:     } else
yading@10:         s->duration = 0;
yading@10: 
yading@10:     *poutbuf = buf;
yading@10:     *poutbuf_size = buf_size;
yading@10:     return next;
yading@10: }
yading@10: 
yading@10: AVCodecParser ff_dca_parser = {
yading@10:     .codec_ids      = { AV_CODEC_ID_DTS },
yading@10:     .priv_data_size = sizeof(DCAParseContext),
yading@10:     .parser_init    = dca_parse_init,
yading@10:     .parser_parse   = dca_parse,
yading@10:     .parser_close   = ff_parse_close,
yading@10: };