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/* |
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* Copyright (c) 2012 Justin Ruggles |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* Vorbis audio parser |
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* |
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* Determines the duration for each packet. |
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*/ |
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#include "libavutil/log.h" |
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#include "get_bits.h" |
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#include "parser.h" |
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#include "xiph.h" |
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#include "vorbis_parser_internal.h" |
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static const AVClass vorbis_parser_class = { |
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.class_name = "Vorbis parser", |
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.item_name = av_default_item_name, |
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.version = LIBAVUTIL_VERSION_INT, |
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}; |
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static int parse_id_header(AVVorbisParseContext *s, |
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const uint8_t *buf, int buf_size) |
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{ |
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/* Id header should be 30 bytes */ |
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✗✓ |
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if (buf_size < 30) { |
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av_log(s, AV_LOG_ERROR, "Id header is too short\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* make sure this is the Id header */ |
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✗✓ |
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if (buf[0] != 1) { |
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av_log(s, AV_LOG_ERROR, "Wrong packet type in Id header\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* check for header signature */ |
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✗✓ |
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if (memcmp(&buf[1], "vorbis", 6)) { |
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av_log(s, AV_LOG_ERROR, "Invalid packet signature in Id header\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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✗✓ |
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if (!(buf[29] & 0x1)) { |
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av_log(s, AV_LOG_ERROR, "Invalid framing bit in Id header\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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s->blocksize[0] = 1 << (buf[28] & 0xF); |
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s->blocksize[1] = 1 << (buf[28] >> 4); |
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return 0; |
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} |
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static int parse_setup_header(AVVorbisParseContext *s, |
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const uint8_t *buf, int buf_size) |
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{ |
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GetBitContext gb, gb0; |
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uint8_t *rev_buf; |
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int i, ret = 0; |
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int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0; |
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/* avoid overread */ |
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✗✓ |
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if (buf_size < 7) { |
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av_log(s, AV_LOG_ERROR, "Setup header is too short\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* make sure this is the Setup header */ |
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✗✓ |
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if (buf[0] != 5) { |
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av_log(s, AV_LOG_ERROR, "Wrong packet type in Setup header\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* check for header signature */ |
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✗✓ |
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if (memcmp(&buf[1], "vorbis", 6)) { |
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av_log(s, AV_LOG_ERROR, "Invalid packet signature in Setup header\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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/* reverse bytes so we can easily read backwards with get_bits() */ |
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✗✓ |
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if (!(rev_buf = av_malloc(buf_size))) { |
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av_log(s, AV_LOG_ERROR, "Out of memory\n"); |
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return AVERROR(ENOMEM); |
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} |
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✓✓ |
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for (i = 0; i < buf_size; i++) |
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193279 |
rev_buf[i] = buf[buf_size - 1 - i]; |
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init_get_bits(&gb, rev_buf, buf_size * 8); |
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got_framing_bit = 0; |
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✓✗ |
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while (get_bits_left(&gb) > 97) { |
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✓✓ |
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if (get_bits1(&gb)) { |
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got_framing_bit = get_bits_count(&gb); |
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break; |
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} |
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} |
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✗✓ |
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if (!got_framing_bit) { |
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av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); |
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ret = AVERROR_INVALIDDATA; |
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goto bad_header; |
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} |
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/* Now we search backwards to find possible valid mode counts. This is not |
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* fool-proof because we could have false positive matches and read too |
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* far, but there isn't really any way to be sure without parsing through |
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* all the many variable-sized fields before the modes. This approach seems |
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* to work well in testing, and it is similar to how it is handled in |
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* liboggz. */ |
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mode_count = 0; |
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got_mode_header = 0; |
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✓✗ |
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while (get_bits_left(&gb) >= 97) { |
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✓✗✓✓ ✓✓ |
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if (get_bits(&gb, 8) > 63 || get_bits(&gb, 16) || get_bits(&gb, 16)) |
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break; |
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skip_bits(&gb, 1); |
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mode_count++; |
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✗✓ |
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if (mode_count > 64) |
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break; |
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gb0 = gb; |
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✓✗ |
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if (get_bits(&gb0, 6) + 1 == mode_count) { |
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got_mode_header = 1; |
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last_mode_count = mode_count; |
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} |
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} |
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✗✓ |
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if (!got_mode_header) { |
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av_log(s, AV_LOG_ERROR, "Invalid Setup header\n"); |
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ret = AVERROR_INVALIDDATA; |
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goto bad_header; |
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} |
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/* All samples I've seen use <= 2 modes, so ask for a sample if we find |
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* more than that, as it is most likely a false positive. If we get any |
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* we may need to approach this the long way and parse the whole Setup |
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* header, but I hope very much that it never comes to that. */ |
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✗✓ |
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if (last_mode_count > 2) { |
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avpriv_request_sample(s, |
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"%d modes (either a false positive or a " |
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"sample from an unknown encoder)", |
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last_mode_count); |
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} |
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/* We're limiting the mode count to 63 so that we know that the previous |
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* block flag will be in the first packet byte. */ |
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✗✓ |
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if (last_mode_count > 63) { |
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av_log(s, AV_LOG_ERROR, "Unsupported mode count: %d\n", |
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last_mode_count); |
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ret = AVERROR_INVALIDDATA; |
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goto bad_header; |
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} |
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s->mode_count = mode_count = last_mode_count; |
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/* Determine the number of bits required to code the mode and turn that |
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* into a bitmask to directly access the mode from the first frame byte. */ |
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s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1; |
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/* The previous window flag is the next bit after the mode */ |
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s->prev_mask = (s->mode_mask | 0x1) + 1; |
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init_get_bits(&gb, rev_buf, buf_size * 8); |
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skip_bits_long(&gb, got_framing_bit); |
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✓✓ |
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for (i = mode_count - 1; i >= 0; i--) { |
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skip_bits_long(&gb, 40); |
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s->mode_blocksize[i] = get_bits1(&gb); |
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} |
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bad_header: |
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av_free(rev_buf); |
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return ret; |
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} |
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static int vorbis_parse_init(AVVorbisParseContext *s, |
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const uint8_t *extradata, int extradata_size) |
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{ |
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const uint8_t *header_start[3]; |
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int header_len[3]; |
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int ret; |
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s->class = &vorbis_parser_class; |
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s->extradata_parsed = 1; |
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✗✓ |
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if ((ret = avpriv_split_xiph_headers(extradata, |
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extradata_size, 30, |
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header_start, header_len)) < 0) { |
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av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n"); |
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return ret; |
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} |
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✗✓ |
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if ((ret = parse_id_header(s, header_start[0], header_len[0])) < 0) |
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return ret; |
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✗✓ |
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if ((ret = parse_setup_header(s, header_start[2], header_len[2])) < 0) |
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return ret; |
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207 |
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s->valid_extradata = 1; |
208 |
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s->previous_blocksize = s->blocksize[s->mode_blocksize[0]]; |
209 |
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210 |
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37 |
return 0; |
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} |
212 |
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213 |
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153725 |
int av_vorbis_parse_frame_flags(AVVorbisParseContext *s, const uint8_t *buf, |
214 |
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int buf_size, int *flags) |
215 |
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{ |
216 |
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153725 |
int duration = 0; |
217 |
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218 |
✓✗✓✓
|
153725 |
if (s->valid_extradata && buf_size > 0) { |
219 |
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int mode, current_blocksize; |
220 |
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153716 |
int previous_blocksize = s->previous_blocksize; |
221 |
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222 |
✗✓ |
153716 |
if (buf[0] & 1) { |
223 |
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/* If the user doesn't care about special packets, it's a bad one. */ |
224 |
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if (!flags) |
225 |
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goto bad_packet; |
226 |
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227 |
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/* Set the flag for which kind of special packet it is. */ |
228 |
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if (buf[0] == 1) |
229 |
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*flags |= VORBIS_FLAG_HEADER; |
230 |
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else if (buf[0] == 3) |
231 |
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*flags |= VORBIS_FLAG_COMMENT; |
232 |
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else if (buf[0] == 5) |
233 |
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*flags |= VORBIS_FLAG_SETUP; |
234 |
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else |
235 |
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goto bad_packet; |
236 |
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237 |
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/* Special packets have no duration. */ |
238 |
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return 0; |
239 |
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240 |
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bad_packet: |
241 |
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av_log(s, AV_LOG_ERROR, "Invalid packet\n"); |
242 |
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return AVERROR_INVALIDDATA; |
243 |
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} |
244 |
✗✓ |
153716 |
if (s->mode_count == 1) |
245 |
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mode = 0; |
246 |
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else |
247 |
|
153716 |
mode = (buf[0] & s->mode_mask) >> 1; |
248 |
✗✓ |
153716 |
if (mode >= s->mode_count) { |
249 |
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av_log(s, AV_LOG_ERROR, "Invalid mode in packet\n"); |
250 |
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return AVERROR_INVALIDDATA; |
251 |
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} |
252 |
✓✓ |
153716 |
if(s->mode_blocksize[mode]){ |
253 |
|
85650 |
int flag = !!(buf[0] & s->prev_mask); |
254 |
|
85650 |
previous_blocksize = s->blocksize[flag]; |
255 |
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} |
256 |
|
153716 |
current_blocksize = s->blocksize[s->mode_blocksize[mode]]; |
257 |
|
153716 |
duration = (previous_blocksize + current_blocksize) >> 2; |
258 |
|
153716 |
s->previous_blocksize = current_blocksize; |
259 |
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} |
260 |
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261 |
|
153725 |
return duration; |
262 |
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} |
263 |
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264 |
|
579 |
int av_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf, |
265 |
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int buf_size) |
266 |
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{ |
267 |
|
579 |
return av_vorbis_parse_frame_flags(s, buf, buf_size, NULL); |
268 |
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} |
269 |
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|
270 |
|
19264 |
void av_vorbis_parse_reset(AVVorbisParseContext *s) |
271 |
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{ |
272 |
✓✗ |
19264 |
if (s->valid_extradata) |
273 |
|
19264 |
s->previous_blocksize = s->blocksize[0]; |
274 |
|
19264 |
} |
275 |
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|
276 |
|
64 |
void av_vorbis_parse_free(AVVorbisParseContext **s) |
277 |
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{ |
278 |
|
64 |
av_freep(s); |
279 |
|
64 |
} |
280 |
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|
281 |
|
37 |
AVVorbisParseContext *av_vorbis_parse_init(const uint8_t *extradata, |
282 |
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int extradata_size) |
283 |
|
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{ |
284 |
|
37 |
AVVorbisParseContext *s = av_mallocz(sizeof(*s)); |
285 |
|
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int ret; |
286 |
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|
287 |
✗✓ |
37 |
if (!s) |
288 |
|
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return NULL; |
289 |
|
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|
290 |
|
37 |
ret = vorbis_parse_init(s, extradata, extradata_size); |
291 |
✗✓ |
37 |
if (ret < 0) { |
292 |
|
|
av_vorbis_parse_free(&s); |
293 |
|
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return NULL; |
294 |
|
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} |
295 |
|
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|
296 |
|
37 |
return s; |
297 |
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} |
298 |
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|
299 |
|
|
#if CONFIG_VORBIS_PARSER |
300 |
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|
301 |
|
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typedef struct VorbisParseContext { |
302 |
|
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AVVorbisParseContext *vp; |
303 |
|
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} VorbisParseContext; |
304 |
|
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|
305 |
|
579 |
static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx, |
306 |
|
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const uint8_t **poutbuf, int *poutbuf_size, |
307 |
|
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const uint8_t *buf, int buf_size) |
308 |
|
|
{ |
309 |
|
579 |
VorbisParseContext *s = s1->priv_data; |
310 |
|
|
int duration; |
311 |
|
|
|
312 |
✓✓✓✗ ✓✗ |
579 |
if (!s->vp && avctx->extradata && avctx->extradata_size) { |
313 |
|
11 |
s->vp = av_vorbis_parse_init(avctx->extradata, avctx->extradata_size); |
314 |
|
|
} |
315 |
✗✓ |
579 |
if (!s->vp) |
316 |
|
|
goto end; |
317 |
|
|
|
318 |
✗✓ |
579 |
if ((duration = av_vorbis_parse_frame(s->vp, buf, buf_size)) >= 0) |
319 |
|
579 |
s1->duration = duration; |
320 |
|
|
|
321 |
|
|
end: |
322 |
|
|
/* always return the full packet. this parser isn't doing any splitting or |
323 |
|
|
combining, only packet analysis */ |
324 |
|
579 |
*poutbuf = buf; |
325 |
|
579 |
*poutbuf_size = buf_size; |
326 |
|
579 |
return buf_size; |
327 |
|
|
} |
328 |
|
|
|
329 |
|
38 |
static void vorbis_parser_close(AVCodecParserContext *ctx) |
330 |
|
|
{ |
331 |
|
38 |
VorbisParseContext *s = ctx->priv_data; |
332 |
|
38 |
av_vorbis_parse_free(&s->vp); |
333 |
|
38 |
} |
334 |
|
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|
335 |
|
|
AVCodecParser ff_vorbis_parser = { |
336 |
|
|
.codec_ids = { AV_CODEC_ID_VORBIS }, |
337 |
|
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.priv_data_size = sizeof(VorbisParseContext), |
338 |
|
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.parser_parse = vorbis_parse, |
339 |
|
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.parser_close = vorbis_parser_close, |
340 |
|
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}; |
341 |
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#endif /* CONFIG_VORBIS_PARSER */ |