| /* | |
| * MLP parser | |
| * Copyright (c) 2007 Ian Caulfield | |
| * | |
| * 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 | |
| * MLP parser | |
| */ | |
| #include <stdint.h> | |
| #include "libavutil/internal.h" | |
| #include "get_bits.h" | |
| #include "parser.h" | |
| #include "mlp_parse.h" | |
| #include "mlp.h" | |
| typedef struct MLPParseContext | |
| { | |
| ParseContext pc; | |
| int bytes_left; | |
| int in_sync; | |
| int num_substreams; | |
| } MLPParseContext; | |
| static av_cold int mlp_init(AVCodecParserContext *s) | |
| { | |
| ff_mlp_init_crc(); | |
| return 0; | |
| } | |
| static int mlp_parse(AVCodecParserContext *s, | |
| AVCodecContext *avctx, | |
| const uint8_t **poutbuf, int *poutbuf_size, | |
| const uint8_t *buf, int buf_size) | |
| { | |
| MLPParseContext *mp = s->priv_data; | |
| int sync_present; | |
| uint8_t parity_bits; | |
| int next; | |
| int ret; | |
| int i, p = 0; | |
| s->key_frame = 0; | |
| *poutbuf_size = 0; | |
| *poutbuf = NULL; | |
| if (buf_size == 0) | |
| return 0; | |
| if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { | |
| next = buf_size; | |
| } else { | |
| if (!mp->in_sync) { | |
| // Not in sync - find a major sync header | |
| for (i = 0; i < buf_size; i++) { | |
| mp->pc.state = (mp->pc.state << 8) | buf[i]; | |
| if ((mp->pc.state & 0xfffffffe) == 0xf8726fba && | |
| // ignore if we do not have the data for the start of header | |
| mp->pc.index + i >= 7) { | |
| mp->in_sync = 1; | |
| mp->bytes_left = 0; | |
| break; | |
| } | |
| } | |
| if (!mp->in_sync) { | |
| if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1) | |
| av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); | |
| return buf_size; | |
| } | |
| if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) { | |
| av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); | |
| return ret; | |
| } | |
| return i - 7; | |
| } | |
| if (mp->bytes_left == 0) { | |
| // Find length of this packet | |
| /* Copy overread bytes from last frame into buffer. */ | |
| for(; mp->pc.overread>0; mp->pc.overread--) { | |
| mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++]; | |
| } | |
| if (mp->pc.index + buf_size < 2) { | |
| if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1) | |
| av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n"); | |
| return buf_size; | |
| } | |
| mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8) | |
| | (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]); | |
| mp->bytes_left = (mp->bytes_left & 0xfff) * 2; | |
| if (mp->bytes_left <= 0) { // prevent infinite loop | |
| goto lost_sync; | |
| } | |
| mp->bytes_left -= mp->pc.index; | |
| } | |
| next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left; | |
| if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) { | |
| mp->bytes_left -= buf_size; | |
| return buf_size; | |
| } | |
| mp->bytes_left = 0; | |
| } | |
| sync_present = buf_size >= 8 && (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba; | |
| if (!sync_present) { | |
| /* The first nibble of a frame is a parity check of the 4-byte | |
| * access unit header and all the 2- or 4-byte substream headers. */ | |
| // Only check when this isn't a sync frame - syncs have a checksum. | |
| s->key_frame = 0; | |
| parity_bits = 0; | |
| for (i = -1; i < mp->num_substreams; i++) { | |
| parity_bits ^= buf[p++]; | |
| parity_bits ^= buf[p++]; | |
| if (i < 0 || buf[p-2] & 0x80) { | |
| parity_bits ^= buf[p++]; | |
| parity_bits ^= buf[p++]; | |
| } | |
| } | |
| if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) { | |
| av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n"); | |
| goto lost_sync; | |
| } | |
| } else { | |
| GetBitContext gb; | |
| MLPHeaderInfo mh; | |
| init_get_bits(&gb, buf + 4, (buf_size - 4) << 3); | |
| if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0) | |
| goto lost_sync; | |
| s->key_frame = 1; | |
| avctx->bits_per_raw_sample = mh.group1_bits; | |
| if (avctx->bits_per_raw_sample > 16) | |
| avctx->sample_fmt = AV_SAMPLE_FMT_S32; | |
| else | |
| avctx->sample_fmt = AV_SAMPLE_FMT_S16; | |
| avctx->sample_rate = mh.group1_samplerate; | |
| avctx->frame_size = | |
| s->duration = mh.access_unit_size; | |
| av_channel_layout_uninit(&avctx->ch_layout); | |
| if (mh.stream_type == 0xbb) { | |
| /* MLP stream */ | |
| av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_mlp); | |
| } else { /* mh.stream_type == 0xba */ | |
| /* TrueHD stream */ | |
| if (!mh.channels_thd_stream2) { | |
| av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream1); | |
| } else { | |
| av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream2); | |
| } | |
| } | |
| if (!mh.is_vbr) /* Stream is CBR */ | |
| avctx->bit_rate = mh.peak_bitrate; | |
| mp->num_substreams = mh.num_substreams; | |
| } | |
| *poutbuf = buf; | |
| *poutbuf_size = buf_size; | |
| return next; | |
| lost_sync: | |
| mp->in_sync = 0; | |
| return 1; | |
| } | |
| const AVCodecParser ff_mlp_parser = { | |
| .codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD }, | |
| .priv_data_size = sizeof(MLPParseContext), | |
| .parser_init = mlp_init, | |
| .parser_parse = mlp_parse, | |
| .parser_close = ff_parse_close, | |
| }; |