/*
* 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 "avcodec.h"
#include "bytestream.h"
#include "opus.h"
#include "parser.h"
typedef struct OpusParseContext {
OpusContext ctx;
OpusPacket pkt;
int extradata_parsed;
ParseContext pc;
int ts_framing;
} OpusParseContext;
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;
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 = 0;
while (bytestream2_peek_byte(&gb) == 0xff)
*payload_len += bytestream2_get_byte(&gb);
*payload_len += 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);
}
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)
{
OpusParseContext *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);
*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)
{
OpusParseContext *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;
}
AVCodecParser ff_opus_parser = {
.codec_ids = { AV_CODEC_ID_OPUS },
.priv_data_size = sizeof(OpusParseContext),
.parser_parse = opus_parse,
.parser_close = ff_parse_close
};