diff options
Diffstat (limited to 'media/ffvpx/libavcodec/vorbis_parser.c')
| -rw-r--r-- | media/ffvpx/libavcodec/vorbis_parser.c | 341 |
1 files changed, 341 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/vorbis_parser.c b/media/ffvpx/libavcodec/vorbis_parser.c new file mode 100644 index 000000000..0b2c97cde --- /dev/null +++ b/media/ffvpx/libavcodec/vorbis_parser.c @@ -0,0 +1,341 @@ +/* + * Copyright (c) 2012 Justin Ruggles + * + * 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 + * Vorbis audio parser + * + * Determines the duration for each packet. + */ + +#include "libavutil/log.h" + +#include "get_bits.h" +#include "parser.h" +#include "xiph.h" +#include "vorbis_parser_internal.h" + +static const AVClass vorbis_parser_class = { + .class_name = "Vorbis parser", + .item_name = av_default_item_name, + .version = LIBAVUTIL_VERSION_INT, +}; + +static int parse_id_header(AVVorbisParseContext *s, + const uint8_t *buf, int buf_size) +{ + /* Id header should be 30 bytes */ + if (buf_size < 30) { + av_log(s, AV_LOG_ERROR, "Id header is too short\n"); + return AVERROR_INVALIDDATA; + } + + /* make sure this is the Id header */ + if (buf[0] != 1) { + av_log(s, AV_LOG_ERROR, "Wrong packet type in Id header\n"); + return AVERROR_INVALIDDATA; + } + + /* check for header signature */ + if (memcmp(&buf[1], "vorbis", 6)) { + av_log(s, AV_LOG_ERROR, "Invalid packet signature in Id header\n"); + return AVERROR_INVALIDDATA; + } + + if (!(buf[29] & 0x1)) { + av_log(s, AV_LOG_ERROR, "Invalid framing bit in Id header\n"); + return AVERROR_INVALIDDATA; + } + + s->blocksize[0] = 1 << (buf[28] & 0xF); + s->blocksize[1] = 1 << (buf[28] >> 4); + + return 0; +} + +static int parse_setup_header(AVVorbisParseContext *s, + const uint8_t *buf, int buf_size) +{ + GetBitContext gb, gb0; + uint8_t *rev_buf; + int i, ret = 0; + int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0; + + /* avoid overread */ + if (buf_size < 7) { + av_log(s, AV_LOG_ERROR, "Setup header is too short\n"); + return AVERROR_INVALIDDATA; + } + + /* make sure this is the Setup header */ + if (buf[0] != 5) { + av_log(s, AV_LOG_ERROR, "Wrong packet type in Setup header\n"); + return AVERROR_INVALIDDATA; + } + + /* check for header signature */ + if (memcmp(&buf[1], "vorbis", 6)) { + av_log(s, AV_LOG_ERROR, "Invalid packet signature in Setup header\n"); + return AVERROR_INVALIDDATA; + } + + /* reverse bytes so we can easily read backwards with get_bits() */ + if (!(rev_buf = av_malloc(buf_size))) { + av_log(s, AV_LOG_ERROR, "Out of memory\n"); + return AVERROR(ENOMEM); + } + for (i = 0; i < buf_size; i++) + rev_buf[i] = buf[buf_size - 1 - i]; + init_get_bits(&gb, rev_buf, buf_size * 8); + + got_framing_bit = 0; + while (get_bits_left(&gb) > 97) { + if (get_bits1(&gb)) { + got_framing_bit = get_bits_count(&gb); + break; + } + } + if (!got_framing_bit) { + av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); + ret = AVERROR_INVALIDDATA; + goto bad_header; + } + + /* Now we search backwards to find possible valid mode counts. This is not + * fool-proof because we could have false positive matches and read too + * far, but there isn't really any way to be sure without parsing through + * all the many variable-sized fields before the modes. This approach seems + * to work well in testing, and it is similar to how it is handled in + * liboggz. */ + mode_count = 0; + got_mode_header = 0; + while (get_bits_left(&gb) >= 97) { + if (get_bits(&gb, 8) > 63 || get_bits(&gb, 16) || get_bits(&gb, 16)) + break; + skip_bits(&gb, 1); + mode_count++; + if (mode_count > 64) + break; + gb0 = gb; + if (get_bits(&gb0, 6) + 1 == mode_count) { + got_mode_header = 1; + last_mode_count = mode_count; + } + } + if (!got_mode_header) { + av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); + ret = AVERROR_INVALIDDATA; + goto bad_header; + } + /* All samples I've seen use <= 2 modes, so ask for a sample if we find + * more than that, as it is most likely a false positive. If we get any + * we may need to approach this the long way and parse the whole Setup + * header, but I hope very much that it never comes to that. */ + if (last_mode_count > 2) { + avpriv_request_sample(s, + "%d modes (either a false positive or a " + "sample from an unknown encoder)", + last_mode_count); + } + /* We're limiting the mode count to 63 so that we know that the previous + * block flag will be in the first packet byte. */ + if (last_mode_count > 63) { + av_log(s, AV_LOG_ERROR, "Unsupported mode count: %d\n", + last_mode_count); + ret = AVERROR_INVALIDDATA; + goto bad_header; + } + s->mode_count = mode_count = last_mode_count; + /* Determine the number of bits required to code the mode and turn that + * into a bitmask to directly access the mode from the first frame byte. */ + s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1; + /* The previous window flag is the next bit after the mode */ + s->prev_mask = (s->mode_mask | 0x1) + 1; + + init_get_bits(&gb, rev_buf, buf_size * 8); + skip_bits_long(&gb, got_framing_bit); + for (i = mode_count - 1; i >= 0; i--) { + skip_bits_long(&gb, 40); + s->mode_blocksize[i] = get_bits1(&gb); + } + +bad_header: + av_free(rev_buf); + return ret; +} + +static int vorbis_parse_init(AVVorbisParseContext *s, + const uint8_t *extradata, int extradata_size) +{ + const uint8_t *header_start[3]; + int header_len[3]; + int ret; + + s->class = &vorbis_parser_class; + s->extradata_parsed = 1; + + if ((ret = avpriv_split_xiph_headers(extradata, + extradata_size, 30, + header_start, header_len)) < 0) { + av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n"); + return ret; + } + + if ((ret = parse_id_header(s, header_start[0], header_len[0])) < 0) + return ret; + + if ((ret = parse_setup_header(s, header_start[2], header_len[2])) < 0) + return ret; + + s->valid_extradata = 1; + s->previous_blocksize = s->blocksize[s->mode_blocksize[0]]; + + return 0; +} + +int av_vorbis_parse_frame_flags(AVVorbisParseContext *s, const uint8_t *buf, + int buf_size, int *flags) +{ + int duration = 0; + + if (s->valid_extradata && buf_size > 0) { + int mode, current_blocksize; + int previous_blocksize = s->previous_blocksize; + + if (buf[0] & 1) { + /* If the user doesn't care about special packets, it's a bad one. */ + if (!flags) + goto bad_packet; + + /* Set the flag for which kind of special packet it is. */ + if (buf[0] == 1) + *flags |= VORBIS_FLAG_HEADER; + else if (buf[0] == 3) + *flags |= VORBIS_FLAG_COMMENT; + else if (buf[0] == 5) + *flags |= VORBIS_FLAG_SETUP; + else + goto bad_packet; + + /* Special packets have no duration. */ + return 0; + +bad_packet: + av_log(s, AV_LOG_ERROR, "Invalid packet\n"); + return AVERROR_INVALIDDATA; + } + if (s->mode_count == 1) + mode = 0; + else + mode = (buf[0] & s->mode_mask) >> 1; + if (mode >= s->mode_count) { + av_log(s, AV_LOG_ERROR, "Invalid mode in packet\n"); + return AVERROR_INVALIDDATA; + } + if(s->mode_blocksize[mode]){ + int flag = !!(buf[0] & s->prev_mask); + previous_blocksize = s->blocksize[flag]; + } + current_blocksize = s->blocksize[s->mode_blocksize[mode]]; + duration = (previous_blocksize + current_blocksize) >> 2; + s->previous_blocksize = current_blocksize; + } + + return duration; +} + +int av_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf, + int buf_size) +{ + return av_vorbis_parse_frame_flags(s, buf, buf_size, NULL); +} + +void av_vorbis_parse_reset(AVVorbisParseContext *s) +{ + if (s->valid_extradata) + s->previous_blocksize = s->blocksize[0]; +} + +void av_vorbis_parse_free(AVVorbisParseContext **s) +{ + av_freep(s); +} + +AVVorbisParseContext *av_vorbis_parse_init(const uint8_t *extradata, + int extradata_size) +{ + AVVorbisParseContext *s = av_mallocz(sizeof(*s)); + int ret; + + if (!s) + return NULL; + + ret = vorbis_parse_init(s, extradata, extradata_size); + if (ret < 0) { + av_vorbis_parse_free(&s); + return NULL; + } + + return s; +} + +#if CONFIG_VORBIS_PARSER + +typedef struct VorbisParseContext { + AVVorbisParseContext *vp; +} VorbisParseContext; + +static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx, + const uint8_t **poutbuf, int *poutbuf_size, + const uint8_t *buf, int buf_size) +{ + VorbisParseContext *s = s1->priv_data; + int duration; + + if (!s->vp && avctx->extradata && avctx->extradata_size) { + s->vp = av_vorbis_parse_init(avctx->extradata, avctx->extradata_size); + } + if (!s->vp) + goto end; + + if ((duration = av_vorbis_parse_frame(s->vp, buf, buf_size)) >= 0) + s1->duration = duration; + +end: + /* always return the full packet. this parser isn't doing any splitting or + combining, only packet analysis */ + *poutbuf = buf; + *poutbuf_size = buf_size; + return buf_size; +} + +static void vorbis_parser_close(AVCodecParserContext *ctx) +{ + VorbisParseContext *s = ctx->priv_data; + av_vorbis_parse_free(&s->vp); +} + +AVCodecParser ff_vorbis_parser = { + .codec_ids = { AV_CODEC_ID_VORBIS }, + .priv_data_size = sizeof(VorbisParseContext), + .parser_parse = vorbis_parse, + .parser_close = vorbis_parser_close, +}; +#endif /* CONFIG_VORBIS_PARSER */ |