/* * DCA parser * Copyright (C) 2004 Gildas Bazin * Copyright (C) 2004 Benjamin Zores * Copyright (C) 2006 Benjamin Larsson * Copyright (C) 2007 Konstantin Shishkov * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "parser.h"#include "dca.h"#include "get_bits.h" typedef struct DCAParseContext {    ParseContext pc;    uint32_t lastmarker;    int size;    int framesize;    int hd_pos;} DCAParseContext; #define IS_MARKER(state, i, buf, buf_size) \ ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \ || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \ || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE) /** * Find the end of the current frame in the bitstream. * @return the position of the first byte of the next frame, or -1 */static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf,                              int buf_size){    int start_found, i;    uint32_t state;    ParseContext *pc = &pc1->pc;     start_found = pc->frame_start_found;    state = pc->state;     i = 0;    if (!start_found) {        for (i = 0; i < buf_size; i++) {            state = (state << 8) | buf[i];            if (IS_MARKER(state, i, buf, buf_size)) {                if (pc1->lastmarker && state == pc1->lastmarker) {                    start_found = 1;                    i++;                    break;                } else if (!pc1->lastmarker) {                    start_found = 1;                    pc1->lastmarker = state;                    i++;                    break;                }            }        }    }    if (start_found) {        for (; i < buf_size; i++) {            pc1->size++;            state = (state << 8) | buf[i];            if (state == DCA_HD_MARKER && !pc1->hd_pos)                pc1->hd_pos = pc1->size;            if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) {                if(pc1->framesize > pc1->size)                    continue;                pc->frame_start_found = 0;                pc->state = -1;                pc1->size = 0;                return i - 3;            }        }    }    pc->frame_start_found = start_found;    pc->state = state;    return END_NOT_FOUND;} static av_cold int dca_parse_init(AVCodecParserContext * s){    DCAParseContext *pc1 = s->priv_data;     pc1->lastmarker = 0;    return 0;} static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration,                            int *sample_rate, int *framesize){    GetBitContext gb;    uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };    int ret, sample_blocks, sr_code;     if (buf_size < 12)        return AVERROR_INVALIDDATA;     if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0)        return ret;     init_get_bits(&gb, hdr, 96);     skip_bits_long(&gb, 39);    sample_blocks = get_bits(&gb, 7) + 1;    if (sample_blocks < 8)        return AVERROR_INVALIDDATA;    *duration = 256 * (sample_blocks / 8);     *framesize = get_bits(&gb, 14) + 1;    if (*framesize < 95)        return AVERROR_INVALIDDATA;     skip_bits(&gb, 6);    sr_code = get_bits(&gb, 4);    *sample_rate = avpriv_dca_sample_rates[sr_code];    if (*sample_rate == 0)        return AVERROR_INVALIDDATA;     return 0;} static int dca_parse(AVCodecParserContext * s,                     AVCodecContext * avctx,                     const uint8_t ** poutbuf, int *poutbuf_size,                     const uint8_t * buf, int buf_size){    DCAParseContext *pc1 = s->priv_data;    ParseContext *pc = &pc1->pc;    int next, duration, sample_rate;     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {        next = buf_size;    } else {        next = dca_find_frame_end(pc1, buf, buf_size);         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {            *poutbuf = NULL;            *poutbuf_size = 0;            return buf_size;        }    }     /* read the duration and sample rate from the frame header */    if (!dca_parse_params(buf, buf_size, &duration, &sample_rate, &pc1->framesize)) {        s->duration = duration;        avctx->sample_rate = sample_rate;    } else        s->duration = 0;     *poutbuf = buf;    *poutbuf_size = buf_size;    return next;} AVCodecParser ff_dca_parser = {    .codec_ids      = { AV_CODEC_ID_DTS },    .priv_data_size = sizeof(DCAParseContext),    .parser_init    = dca_parse_init,    .parser_parse   = dca_parse,    .parser_close   = ff_parse_close,};