mirror of https://github.com/FFmpeg/FFmpeg.git
This also allows for removing some of the Vorbis-related hacks.pull/3/merge
Justin Ruggles
13 years ago
parent
737ca4482b
commit
5602a464c9
9 changed files with 346 additions and 7 deletions
@ -0,0 +1,270 @@ |
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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 Libav. |
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* |
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* Libav 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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* Libav 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 Libav; 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 "get_bits.h" |
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#include "parser.h" |
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#include "xiph.h" |
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#include "vorbis_parser.h" |
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static int parse_id_header(AVCodecContext *avctx, VorbisParseContext *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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if (buf_size < 30) { |
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av_log(avctx, AV_LOG_ERROR, "Id header is too short\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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|
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/* make sure this is the Id header */ |
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if (buf[0] != 1) { |
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av_log(avctx, 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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if (memcmp(&buf[1], "vorbis", 6)) { |
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av_log(avctx, 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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if (!(buf[29] & 0x1)) { |
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av_log(avctx, 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(AVCodecContext *avctx, VorbisParseContext *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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if (buf_size < 7) { |
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av_log(avctx, AV_LOG_ERROR, "Setup header is too short\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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|
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/* make sure this is the Setup header */ |
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if (buf[0] != 5) { |
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av_log(avctx, 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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if (memcmp(&buf[1], "vorbis", 6)) { |
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av_log(avctx, 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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if (!(rev_buf = av_malloc(buf_size))) { |
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av_log(avctx, AV_LOG_ERROR, "Out of memory\n"); |
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return AVERROR(ENOMEM); |
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} |
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for (i = 0; i < buf_size; i++) |
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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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while (get_bits_left(&gb) > 97) { |
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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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if (!got_framing_bit) { |
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av_log(avctx, 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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while (get_bits_left(&gb) >= 97) { |
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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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if (mode_count > 64) |
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break; |
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gb0 = gb; |
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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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if (!got_mode_header) { |
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av_log(avctx, 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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if (last_mode_count > 2) { |
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av_log_ask_for_sample(avctx, "%d modes found. This is either a false " |
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"positive or a sample from an unknown encoder.\n", |
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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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if (last_mode_count > 63) { |
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av_log(avctx, 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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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] = s->blocksize[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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int avpriv_vorbis_parse_extradata(AVCodecContext *avctx, VorbisParseContext *s) |
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{ |
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uint8_t *header_start[3]; |
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int header_len[3]; |
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int ret; |
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s->avctx = avctx; |
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s->extradata_parsed = 1; |
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if ((ret = avpriv_split_xiph_headers(avctx->extradata, |
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avctx->extradata_size, 30, |
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header_start, header_len)) < 0) { |
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av_log(avctx, AV_LOG_ERROR, "Extradata corrupt.\n"); |
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return ret; |
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} |
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if ((ret = parse_id_header(avctx, s, header_start[0], header_len[0])) < 0) |
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return ret; |
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if ((ret = parse_setup_header(avctx, s, header_start[2], header_len[2])) < 0) |
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return ret; |
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s->valid_extradata = 1; |
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s->previous_blocksize = s->mode_blocksize[0]; |
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return 0; |
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} |
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int avpriv_vorbis_parse_frame(VorbisParseContext *s, const uint8_t *buf, |
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int buf_size) |
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{ |
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int duration = 0; |
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if (s->valid_extradata && buf_size > 0) { |
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int mode, current_blocksize; |
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int previous_blocksize = s->previous_blocksize; |
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if (buf[0] & 1) { |
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av_log(s->avctx, AV_LOG_ERROR, "Invalid packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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if (s->mode_count == 1) |
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mode = 0; |
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else |
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mode = (buf[0] & s->mode_mask) >> 1; |
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if (mode >= s->mode_count) { |
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av_log(s->avctx, AV_LOG_ERROR, "Invalid mode in packet\n"); |
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return AVERROR_INVALIDDATA; |
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} |
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if (mode) { |
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int flag = !!(buf[0] & s->prev_mask); |
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previous_blocksize = s->blocksize[flag]; |
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} |
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current_blocksize = s->mode_blocksize[mode]; |
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duration = (previous_blocksize + current_blocksize) >> 2; |
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s->previous_blocksize = current_blocksize; |
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} |
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return duration; |
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} |
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void avpriv_vorbis_parse_reset(VorbisParseContext *s) |
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{ |
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if (s->valid_extradata) |
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s->previous_blocksize = s->mode_blocksize[0]; |
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} |
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#if CONFIG_VORBIS_PARSER |
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static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx, |
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const uint8_t **poutbuf, int *poutbuf_size, |
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const uint8_t *buf, int buf_size) |
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{ |
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VorbisParseContext *s = s1->priv_data; |
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int duration; |
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if (!s->extradata_parsed && avctx->extradata && avctx->extradata_size) |
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if (avpriv_vorbis_parse_extradata(avctx, s)) |
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goto end; |
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if ((duration = avpriv_vorbis_parse_frame(s, buf, buf_size)) >= 0) |
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s1->duration = duration; |
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end: |
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/* always return the full packet. this parser isn't doing any splitting or
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combining, only packet analysis */ |
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*poutbuf = buf; |
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*poutbuf_size = buf_size; |
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return buf_size; |
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} |
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AVCodecParser ff_vorbis_parser = { |
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.codec_ids = { CODEC_ID_VORBIS }, |
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.priv_data_size = sizeof(VorbisParseContext), |
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.parser_parse = vorbis_parse, |
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}; |
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#endif /* CONFIG_VORBIS_PARSER */ |
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@ -0,0 +1,68 @@ |
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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 Libav. |
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* |
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* Libav 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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* Libav 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 Libav; 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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#ifndef AVCODEC_VORBIS_PARSER_H |
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#define AVCODEC_VORBIS_PARSER_H |
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#include "avcodec.h" |
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typedef struct VorbisParseContext { |
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AVCodecContext *avctx; ///< codec context
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int extradata_parsed; ///< we have attempted to parse extradata
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int valid_extradata; ///< extradata is valid, so we can calculate duration
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int blocksize[2]; ///< short and long window sizes
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int previous_blocksize; ///< previous window size
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int mode_blocksize[64]; ///< window size mapping for each mode
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int mode_count; ///< number of modes
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int mode_mask; ///< bitmask used to get the mode in each packet
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int prev_mask; ///< bitmask used to get the previous mode flag in each packet
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} VorbisParseContext; |
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/**
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* Initialize the Vorbis parser using headers in the extradata. |
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* |
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* @param avctx codec context |
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* @param s Vorbis parser context |
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*/ |
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int avpriv_vorbis_parse_extradata(AVCodecContext *avctx, VorbisParseContext *s); |
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/**
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* Get the duration for a Vorbis packet. |
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* |
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* avpriv_vorbis_parse_extradata() must have been successfully called prior to |
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* this in order for a correct duration to be returned. |
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* |
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* @param s Vorbis parser context |
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* @param buf buffer containing a Vorbis frame |
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* @param buf_size size of the buffer |
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*/ |
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int avpriv_vorbis_parse_frame(VorbisParseContext *s, const uint8_t *buf, |
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int buf_size); |
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void avpriv_vorbis_parse_reset(VorbisParseContext *s); |
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#endif /* AVCODEC_VORBIS_PARSER_H */ |
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