/* * Copyright (c) 2013-2014 Mozilla Corporation * * 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 * Opus parser * * Determines the duration for each packet. */ #include "libavutil/mem.h"#include "avcodec.h"#include "bytestream.h"#include "opus.h"#include "parse.h"#include "parser.h" typedef struct OpusParserContext {    ParseContext pc;    OpusParseContext ctx;    OpusPacket pkt;    int extradata_parsed;    int ts_framing;} OpusParserContext; static const uint8_t *parse_opus_ts_header(const uint8_t *start, int *payload_len, int buf_len){    const uint8_t *buf = start + 1;    int start_trim_flag, end_trim_flag, control_extension_flag, control_extension_length;    uint8_t flags;    uint64_t payload_len_tmp;     GetByteContext gb;    bytestream2_init(&gb, buf, buf_len);     flags = bytestream2_get_byte(&gb);    start_trim_flag        = (flags >> 4) & 1;    end_trim_flag          = (flags >> 3) & 1;    control_extension_flag = (flags >> 2) & 1;     payload_len_tmp = *payload_len = 0;    while (bytestream2_peek_byte(&gb) == 0xff)        payload_len_tmp += bytestream2_get_byte(&gb);     payload_len_tmp += bytestream2_get_byte(&gb);     if (start_trim_flag)        bytestream2_skip(&gb, 2);    if (end_trim_flag)        bytestream2_skip(&gb, 2);    if (control_extension_flag) {        control_extension_length = bytestream2_get_byte(&gb);        bytestream2_skip(&gb, control_extension_length);    }     if (bytestream2_tell(&gb) + payload_len_tmp > buf_len)        return NULL;     *payload_len = payload_len_tmp;     return buf + bytestream2_tell(&gb);} /** * 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 opus_find_frame_end(AVCodecParserContext *ctx, AVCodecContext *avctx,                               const uint8_t *buf, int buf_size, int *header_len){    OpusParserContext *s = ctx->priv_data;    ParseContext *pc    = &s->pc;    int ret, start_found, i = 0, payload_len = 0;    const uint8_t *payload;    uint32_t state;    uint16_t hdr;    *header_len = 0;     if (!buf_size)        return 0;     start_found = pc->frame_start_found;    state = pc->state;    payload = buf;     /* Check if we're using Opus in MPEG-TS framing */    if (!s->ts_framing && buf_size > 2) {        hdr = AV_RB16(buf);        if ((hdr & OPUS_TS_MASK) == OPUS_TS_HEADER)            s->ts_framing = 1;    }     if (s->ts_framing && !start_found) {        for (i = 0; i < buf_size-2; i++) {            state = (state << 8) | payload[i];            if ((state & OPUS_TS_MASK) == OPUS_TS_HEADER) {                payload = parse_opus_ts_header(payload, &payload_len, buf_size - i);                if (!payload) {                    av_log(avctx, AV_LOG_ERROR, "Error parsing Ogg TS header.\n");                    return AVERROR_INVALIDDATA;                }                *header_len = payload - buf;                start_found = 1;                break;            }        }    }     if (!s->ts_framing)        payload_len = buf_size;     if (avctx->extradata && !s->extradata_parsed) {        ret = ff_opus_parse_extradata(avctx, &s->ctx);        if (ret < 0) {            av_log(avctx, AV_LOG_ERROR, "Error parsing Ogg extradata.\n");            return AVERROR_INVALIDDATA;        }        av_freep(&s->ctx.channel_maps);        s->extradata_parsed = 1;    }     if (payload_len <= buf_size && (!s->ts_framing || start_found)) {        ret = ff_opus_parse_packet(&s->pkt, payload, payload_len, s->ctx.nb_streams > 1);        if (ret < 0) {            av_log(avctx, AV_LOG_ERROR, "Error parsing Opus packet header.\n");            pc->frame_start_found = 0;            return AVERROR_INVALIDDATA;        }         ctx->duration = s->pkt.frame_count * s->pkt.frame_duration;    }     if (s->ts_framing) {        if (start_found) {            if (payload_len + *header_len <= buf_size) {                pc->frame_start_found = 0;                pc->state             = -1;                return payload_len + *header_len;            }        }         pc->frame_start_found = start_found;        pc->state = state;        return END_NOT_FOUND;    }     return buf_size;} static int opus_parse(AVCodecParserContext *ctx, AVCodecContext *avctx,                       const uint8_t **poutbuf, int *poutbuf_size,                       const uint8_t *buf, int buf_size){    OpusParserContext *s = ctx->priv_data;    ParseContext *pc    = &s->pc;    int next, header_len;     next = opus_find_frame_end(ctx, avctx, buf, buf_size, &header_len);     if (s->ts_framing && next != AVERROR_INVALIDDATA &&        ff_combine_frame(pc, next, &buf, &buf_size) < 0) {        *poutbuf      = NULL;        *poutbuf_size = 0;        return buf_size;    }     if (next == AVERROR_INVALIDDATA){        *poutbuf      = NULL;        *poutbuf_size = 0;        return buf_size;    }     *poutbuf      = buf + header_len;    *poutbuf_size = buf_size - header_len;    return next;} const AVCodecParser ff_opus_parser = {    .codec_ids      = { AV_CODEC_ID_OPUS },    .priv_data_size = sizeof(OpusParserContext),    .parser_parse   = opus_parse,    .parser_close   = ff_parse_close};