ffmpeg / libavformat / westwood.c @ 5509bffa
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/*
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* Westwood Studios Multimedia Formats Demuxer (VQA, AUD)
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* Copyright (c) 2003 The ffmpeg Project
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; 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 westwood.c
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* Westwood Studios VQA & AUD file demuxers
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* by Mike Melanson (melanson@pcisys.net)
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* for more information on the Westwood file formats, visit:
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* http://www.pcisys.net/~melanson/codecs/
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* http://www.geocities.com/SiliconValley/8682/aud3.txt
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*
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* Implementation note: There is no definite file signature for AUD files.
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* The demuxer uses a probabilistic strategy for content detection. This
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* entails performing sanity checks on certain header values in order to
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* qualify a file. Refer to wsaud_probe() for the precise parameters.
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*/
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#include "avformat.h" |
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#define AUD_HEADER_SIZE 12 |
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#define AUD_CHUNK_PREAMBLE_SIZE 8 |
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#define AUD_CHUNK_SIGNATURE 0x0000DEAF |
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#define FORM_TAG MKBETAG('F', 'O', 'R', 'M') |
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#define WVQA_TAG MKBETAG('W', 'V', 'Q', 'A') |
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#define VQHD_TAG MKBETAG('V', 'Q', 'H', 'D') |
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#define FINF_TAG MKBETAG('F', 'I', 'N', 'F') |
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#define SND0_TAG MKBETAG('S', 'N', 'D', '0') |
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#define SND2_TAG MKBETAG('S', 'N', 'D', '2') |
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#define VQFR_TAG MKBETAG('V', 'Q', 'F', 'R') |
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/* don't know what these tags are for, but acknowledge their existence */
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#define CINF_TAG MKBETAG('C', 'I', 'N', 'F') |
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#define CINH_TAG MKBETAG('C', 'I', 'N', 'H') |
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#define CIND_TAG MKBETAG('C', 'I', 'N', 'D') |
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#define PINF_TAG MKBETAG('P', 'I', 'N', 'F') |
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#define PINH_TAG MKBETAG('P', 'I', 'N', 'H') |
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#define PIND_TAG MKBETAG('P', 'I', 'N', 'D') |
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#define VQA_HEADER_SIZE 0x2A |
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#define VQA_FRAMERATE 15 |
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#define VQA_VIDEO_PTS_INC (90000 / VQA_FRAMERATE) |
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#define VQA_PREAMBLE_SIZE 8 |
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typedef struct WsAudDemuxContext { |
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int audio_samplerate;
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int audio_channels;
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int audio_bits;
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int audio_type;
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int audio_stream_index;
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int64_t audio_frame_counter; |
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} WsAudDemuxContext; |
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typedef struct WsVqaDemuxContext { |
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int audio_samplerate;
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int audio_channels;
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int audio_bits;
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int audio_stream_index;
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int video_stream_index;
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int64_t audio_frame_counter; |
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int64_t video_pts; |
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} WsVqaDemuxContext; |
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static int wsaud_probe(AVProbeData *p) |
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{ |
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int field;
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/* Probabilistic content detection strategy: There is no file signature
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* so perform sanity checks on various header parameters:
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* 8000 <= sample rate (16 bits) <= 48000 ==> 40001 acceptable numbers
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* compression type (8 bits) = 1 or 99 ==> 2 acceptable numbers
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* There is a total of 24 bits. The number space contains 2^24 =
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* 16777216 numbers. There are 40001 * 2 = 80002 acceptable combinations
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* of numbers. There is a 80002/16777216 = 0.48% chance of a false
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* positive.
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*/
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if (p->buf_size < AUD_HEADER_SIZE)
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return 0; |
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/* check sample rate */
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field = LE_16(&p->buf[0]);
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if ((field < 8000) || (field > 48000)) |
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return 0; |
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/* note: only check for WS IMA (type 99) right now since there is no
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* support for type 1 */
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if (p->buf[11] != 99) |
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return 0; |
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/* return 1/2 certainty since this file check is a little sketchy */
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return AVPROBE_SCORE_MAX / 2; |
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} |
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static int wsaud_read_header(AVFormatContext *s, |
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AVFormatParameters *ap) |
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{ |
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WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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AVStream *st; |
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unsigned char header[AUD_HEADER_SIZE]; |
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if (get_buffer(pb, header, AUD_HEADER_SIZE) != AUD_HEADER_SIZE)
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return AVERROR_IO;
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wsaud->audio_samplerate = LE_16(&header[0]);
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if (header[11] == 99) |
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wsaud->audio_type = CODEC_ID_ADPCM_IMA_WS; |
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else
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return AVERROR_INVALIDDATA;
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/* flag 0 indicates stereo */
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wsaud->audio_channels = (header[10] & 0x1) + 1; |
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/* flag 1 indicates 16 bit audio */
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wsaud->audio_bits = (((header[10] & 0x2) >> 1) + 1) * 8; |
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/* initialize the audio decoder stream */
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st = av_new_stream(s, 0);
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if (!st)
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return AVERROR_NOMEM;
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av_set_pts_info(st, 33, 1, wsaud->audio_samplerate); |
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st->codec->codec_type = CODEC_TYPE_AUDIO; |
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st->codec->codec_id = wsaud->audio_type; |
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st->codec->codec_tag = 0; /* no tag */ |
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st->codec->channels = wsaud->audio_channels; |
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st->codec->sample_rate = wsaud->audio_samplerate; |
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st->codec->bits_per_sample = wsaud->audio_bits; |
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st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * |
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st->codec->bits_per_sample / 4;
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st->codec->block_align = st->codec->channels * st->codec->bits_per_sample; |
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wsaud->audio_stream_index = st->index; |
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wsaud->audio_frame_counter = 0;
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return 0; |
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} |
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static int wsaud_read_packet(AVFormatContext *s, |
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AVPacket *pkt) |
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{ |
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WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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unsigned char preamble[AUD_CHUNK_PREAMBLE_SIZE]; |
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unsigned int chunk_size; |
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int ret = 0; |
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if (get_buffer(pb, preamble, AUD_CHUNK_PREAMBLE_SIZE) !=
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AUD_CHUNK_PREAMBLE_SIZE) |
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return AVERROR_IO;
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/* validate the chunk */
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if (LE_32(&preamble[4]) != AUD_CHUNK_SIGNATURE) |
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return AVERROR_INVALIDDATA;
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chunk_size = LE_16(&preamble[0]);
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ret= av_get_packet(pb, pkt, chunk_size); |
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if (ret != chunk_size)
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return AVERROR_IO;
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pkt->stream_index = wsaud->audio_stream_index; |
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pkt->pts = wsaud->audio_frame_counter; |
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pkt->pts /= wsaud->audio_samplerate; |
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/* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
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wsaud->audio_frame_counter += (chunk_size * 2) / wsaud->audio_channels;
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return ret;
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} |
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static int wsaud_read_close(AVFormatContext *s) |
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{ |
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// WsAudDemuxContext *wsaud = (WsAudDemuxContext *)s->priv_data;
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return 0; |
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} |
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static int wsvqa_probe(AVProbeData *p) |
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{ |
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/* need 12 bytes to qualify */
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if (p->buf_size < 12) |
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return 0; |
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/* check for the VQA signatures */
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if ((BE_32(&p->buf[0]) != FORM_TAG) || |
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(BE_32(&p->buf[8]) != WVQA_TAG))
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return 0; |
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return AVPROBE_SCORE_MAX;
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} |
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static int wsvqa_read_header(AVFormatContext *s, |
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AVFormatParameters *ap) |
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{ |
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WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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AVStream *st; |
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unsigned char *header; |
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unsigned char scratch[VQA_PREAMBLE_SIZE]; |
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unsigned int chunk_tag; |
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unsigned int chunk_size; |
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/* initialize the video decoder stream */
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st = av_new_stream(s, 0);
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if (!st)
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return AVERROR_NOMEM;
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av_set_pts_info(st, 33, 1, 90000); |
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wsvqa->video_stream_index = st->index; |
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st->codec->codec_type = CODEC_TYPE_VIDEO; |
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st->codec->codec_id = CODEC_ID_WS_VQA; |
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st->codec->codec_tag = 0; /* no fourcc */ |
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/* skip to the start of the VQA header */
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url_fseek(pb, 20, SEEK_SET);
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/* the VQA header needs to go to the decoder */
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st->codec->extradata_size = VQA_HEADER_SIZE; |
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st->codec->extradata = av_mallocz(VQA_HEADER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE); |
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header = (unsigned char *)st->codec->extradata; |
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if (get_buffer(pb, st->codec->extradata, VQA_HEADER_SIZE) !=
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VQA_HEADER_SIZE) { |
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av_free(st->codec->extradata); |
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return AVERROR_IO;
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} |
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st->codec->width = LE_16(&header[6]);
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st->codec->height = LE_16(&header[8]);
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/* initialize the audio decoder stream is sample rate is non-zero */
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if (LE_16(&header[24])) { |
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st = av_new_stream(s, 0);
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if (!st)
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return AVERROR_NOMEM;
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av_set_pts_info(st, 33, 1, 90000); |
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st->codec->codec_type = CODEC_TYPE_AUDIO; |
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st->codec->codec_id = CODEC_ID_ADPCM_IMA_WS; |
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st->codec->codec_tag = 0; /* no tag */ |
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st->codec->sample_rate = LE_16(&header[24]);
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st->codec->channels = header[26];
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st->codec->bits_per_sample = 16;
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st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * |
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st->codec->bits_per_sample / 4;
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st->codec->block_align = st->codec->channels * st->codec->bits_per_sample; |
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wsvqa->audio_stream_index = st->index; |
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wsvqa->audio_samplerate = st->codec->sample_rate; |
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wsvqa->audio_channels = st->codec->channels; |
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wsvqa->audio_frame_counter = 0;
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} |
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/* there are 0 or more chunks before the FINF chunk; iterate until
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* FINF has been skipped and the file will be ready to be demuxed */
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do {
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if (get_buffer(pb, scratch, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE) {
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av_free(st->codec->extradata); |
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return AVERROR_IO;
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} |
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chunk_tag = BE_32(&scratch[0]);
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chunk_size = BE_32(&scratch[4]);
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/* catch any unknown header tags, for curiousity */
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switch (chunk_tag) {
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case CINF_TAG:
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case CINH_TAG:
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case CIND_TAG:
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case PINF_TAG:
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case PINH_TAG:
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case PIND_TAG:
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case FINF_TAG:
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break;
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default:
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av_log (s, AV_LOG_ERROR, " note: unknown chunk seen (%c%c%c%c)\n",
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scratch[0], scratch[1], |
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scratch[2], scratch[3]); |
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break;
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} |
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url_fseek(pb, chunk_size, SEEK_CUR); |
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} while (chunk_tag != FINF_TAG);
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wsvqa->video_pts = wsvqa->audio_frame_counter = 0;
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return 0; |
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} |
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static int wsvqa_read_packet(AVFormatContext *s, |
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AVPacket *pkt) |
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{ |
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WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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int ret = 0; |
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unsigned char preamble[VQA_PREAMBLE_SIZE]; |
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unsigned int chunk_type; |
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unsigned int chunk_size; |
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int skip_byte;
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if (get_buffer(pb, preamble, VQA_PREAMBLE_SIZE) != VQA_PREAMBLE_SIZE)
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return AVERROR_IO;
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chunk_type = BE_32(&preamble[0]);
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chunk_size = BE_32(&preamble[4]);
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skip_byte = chunk_size & 0x01;
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if ((chunk_type == SND2_TAG) || (chunk_type == VQFR_TAG)) {
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av_get_packet(pb, pkt, chunk_size); |
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if (ret != chunk_size) {
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ret = AVERROR_IO; |
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} |
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if (chunk_type == SND2_TAG) {
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pkt->stream_index = wsvqa->audio_stream_index; |
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pkt->pts = 90000;
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pkt->pts *= wsvqa->audio_frame_counter; |
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pkt->pts /= wsvqa->audio_samplerate; |
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/* 2 samples/byte, 1 or 2 samples per frame depending on stereo */
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wsvqa->audio_frame_counter += (chunk_size * 2) /
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wsvqa->audio_channels; |
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} else {
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pkt->stream_index = wsvqa->video_stream_index; |
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pkt->pts = wsvqa->video_pts; |
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wsvqa->video_pts += VQA_VIDEO_PTS_INC; |
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} |
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} else
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return AVERROR_INVALIDDATA;
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/* stay on 16-bit alignment */
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if (skip_byte)
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url_fseek(pb, 1, SEEK_CUR);
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return ret;
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} |
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static int wsvqa_read_close(AVFormatContext *s) |
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{ |
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// WsVqaDemuxContext *wsvqa = (WsVqaDemuxContext *)s->priv_data;
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return 0; |
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} |
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static AVInputFormat wsaud_iformat = {
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"wsaud",
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"Westwood Studios audio format",
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sizeof(WsAudDemuxContext),
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wsaud_probe, |
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wsaud_read_header, |
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wsaud_read_packet, |
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wsaud_read_close, |
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}; |
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static AVInputFormat wsvqa_iformat = {
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"wsvqa",
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"Westwood Studios VQA format",
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sizeof(WsVqaDemuxContext),
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wsvqa_probe, |
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wsvqa_read_header, |
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wsvqa_read_packet, |
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wsvqa_read_close, |
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}; |
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int westwood_init(void) |
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{ |
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av_register_input_format(&wsaud_iformat); |
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av_register_input_format(&wsvqa_iformat); |
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return 0; |
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} |