320 lines
11 KiB
C
320 lines
11 KiB
C
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/*
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* xWMA demuxer
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* Copyright (c) 2011 Max Horn
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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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#include <inttypes.h>
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#include <stdint.h>
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#include "avformat.h"
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#include "internal.h"
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#include "riff.h"
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/*
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* Demuxer for xWMA, a Microsoft audio container used by XAudio 2.
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*/
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typedef struct XWMAContext {
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int64_t data_end;
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} XWMAContext;
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static int xwma_probe(const AVProbeData *p)
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{
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if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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static int xwma_read_header(AVFormatContext *s)
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{
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int64_t size;
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int ret = 0;
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uint32_t dpds_table_size = 0;
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uint32_t *dpds_table = NULL;
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unsigned int tag;
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AVIOContext *pb = s->pb;
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AVStream *st;
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XWMAContext *xwma = s->priv_data;
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int i;
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/* The following code is mostly copied from wav.c, with some
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* minor alterations.
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*/
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/* check RIFF header */
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tag = avio_rl32(pb);
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if (tag != MKTAG('R', 'I', 'F', 'F'))
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return AVERROR_INVALIDDATA;
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avio_rl32(pb); /* file size */
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tag = avio_rl32(pb);
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if (tag != MKTAG('X', 'W', 'M', 'A'))
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return AVERROR_INVALIDDATA;
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/* parse fmt header */
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tag = avio_rl32(pb);
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if (tag != MKTAG('f', 'm', 't', ' '))
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return AVERROR_INVALIDDATA;
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size = avio_rl32(pb);
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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ret = ff_get_wav_header(s, pb, st->codecpar, size, 0);
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if (ret < 0)
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return ret;
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st->need_parsing = AVSTREAM_PARSE_NONE;
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/* XWMA encoder only allows a few channel/sample rate/bitrate combinations,
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* but some create identical files with fake bitrate (1ch 22050hz at
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* 20/48/192kbps are all 20kbps, with the exact same codec data).
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* Decoder needs correct bitrate to work, so it's normalized here. */
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if (st->codecpar->codec_id == AV_CODEC_ID_WMAV2) {
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int ch = st->codecpar->channels;
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int sr = st->codecpar->sample_rate;
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int br = st->codecpar->bit_rate;
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if (ch == 1) {
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if (sr == 22050 && (br==48000 || br==192000))
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br = 20000;
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else if (sr == 32000 && (br==48000 || br==192000))
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br = 20000;
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else if (sr == 44100 && (br==96000 || br==192000))
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br = 48000;
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}
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else if (ch == 2) {
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if (sr == 22050 && (br==48000 || br==192000))
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br = 32000;
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else if (sr == 32000 && (br==192000))
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br = 48000;
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}
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st->codecpar->bit_rate = br;
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}
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/* Normally xWMA can only contain WMAv2 with 1/2 channels,
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* and WMAPRO with 6 channels. */
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if (st->codecpar->codec_id != AV_CODEC_ID_WMAV2 &&
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st->codecpar->codec_id != AV_CODEC_ID_WMAPRO) {
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avpriv_request_sample(s, "Unexpected codec (tag %s; id %d)",
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av_fourcc2str(st->codecpar->codec_tag),
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st->codecpar->codec_id);
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} else {
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/* xWMA shouldn't have extradata. But the WMA codecs require it,
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* so we provide our own fake extradata.
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*
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* First, check that there really was no extradata in the header. If
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* there was, then try to use it, after asking the user to provide a
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* sample of this unusual file.
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*/
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if (st->codecpar->extradata_size != 0) {
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/* Surprise, surprise: We *did* get some extradata. No idea
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* if it will work, but just go on and try it, after asking
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* the user for a sample.
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*/
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avpriv_request_sample(s, "Unexpected extradata (%d bytes)",
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st->codecpar->extradata_size);
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} else if (st->codecpar->codec_id == AV_CODEC_ID_WMAPRO) {
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if ((ret = ff_alloc_extradata(st->codecpar, 18)) < 0)
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return ret;
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memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
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st->codecpar->extradata[ 0] = st->codecpar->bits_per_coded_sample;
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st->codecpar->extradata[14] = 224;
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} else {
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if ((ret = ff_alloc_extradata(st->codecpar, 6)) < 0)
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return ret;
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memset(st->codecpar->extradata, 0, st->codecpar->extradata_size);
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/* setup extradata with our experimentally obtained value */
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st->codecpar->extradata[4] = 31;
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}
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}
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if (!st->codecpar->channels) {
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av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
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st->codecpar->channels);
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return AVERROR_INVALIDDATA;
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}
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if (!st->codecpar->bits_per_coded_sample) {
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av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
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st->codecpar->bits_per_coded_sample);
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return AVERROR_INVALIDDATA;
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}
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/* set the sample rate */
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avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
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/* parse the remaining RIFF chunks */
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for (;;) {
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if (pb->eof_reached) {
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ret = AVERROR_EOF;
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goto fail;
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}
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/* read next chunk tag */
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tag = avio_rl32(pb);
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size = avio_rl32(pb);
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if (tag == MKTAG('d', 'a', 't', 'a')) {
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/* We assume that the data chunk comes last. */
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break;
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} else if (tag == MKTAG('d','p','d','s')) {
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/* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
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* decoded packet cumulative data size array, each element is the
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* number of bytes accumulated after the corresponding xWMA packet
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* is decoded in order."
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*
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* Each packet has size equal to st->codecpar->block_align, which in
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* all cases I saw so far was always 2230. Thus, we can use the
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* dpds data to compute a seeking index.
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*/
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/* Error out if there is more than one dpds chunk. */
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if (dpds_table) {
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av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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/* Compute the number of entries in the dpds chunk. */
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if (size & 3) { /* Size should be divisible by four */
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av_log(s, AV_LOG_WARNING,
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"dpds chunk size %"PRId64" not divisible by 4\n", size);
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}
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dpds_table_size = size / 4;
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if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {
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av_log(s, AV_LOG_ERROR,
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"dpds chunk size %"PRId64" invalid\n", size);
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return AVERROR_INVALIDDATA;
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}
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/* Allocate some temporary storage to keep the dpds data around.
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* for processing later on.
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*/
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dpds_table = av_malloc_array(dpds_table_size, sizeof(uint32_t));
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if (!dpds_table) {
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return AVERROR(ENOMEM);
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}
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for (i = 0; i < dpds_table_size; ++i) {
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dpds_table[i] = avio_rl32(pb);
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size -= 4;
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}
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}
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avio_skip(pb, size);
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}
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/* Determine overall data length */
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if (size < 0) {
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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if (!size) {
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xwma->data_end = INT64_MAX;
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} else
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xwma->data_end = avio_tell(pb) + size;
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if (dpds_table && dpds_table_size) {
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int64_t cur_pos;
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const uint32_t bytes_per_sample
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= (st->codecpar->channels * st->codecpar->bits_per_coded_sample) >> 3;
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/* Estimate the duration from the total number of output bytes. */
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const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
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if (!bytes_per_sample) {
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av_log(s, AV_LOG_ERROR,
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"Invalid bits_per_coded_sample %d for %d channels\n",
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st->codecpar->bits_per_coded_sample, st->codecpar->channels);
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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st->duration = total_decoded_bytes / bytes_per_sample;
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/* Use the dpds data to build a seek table. We can only do this after
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* we know the offset to the data chunk, as we need that to determine
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* the actual offset to each input block.
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* Note: If we allowed ourselves to assume that the data chunk always
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* follows immediately after the dpds block, we could of course guess
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* the data block's start offset already while reading the dpds chunk.
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* I decided against that, just in case other chunks ever are
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* discovered.
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*/
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cur_pos = avio_tell(pb);
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for (i = 0; i < dpds_table_size; ++i) {
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/* From the number of output bytes that would accumulate in the
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* output buffer after decoding the first (i+1) packets, we compute
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* an offset / timestamp pair.
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*/
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av_add_index_entry(st,
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cur_pos + (i+1) * st->codecpar->block_align, /* pos */
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dpds_table[i] / bytes_per_sample, /* timestamp */
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st->codecpar->block_align, /* size */
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0, /* duration */
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AVINDEX_KEYFRAME);
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}
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} else if (st->codecpar->bit_rate) {
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/* No dpds chunk was present (or only an empty one), so estimate
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* the total duration using the average bits per sample and the
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* total data length.
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*/
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st->duration = (size<<3) * st->codecpar->sample_rate / st->codecpar->bit_rate;
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}
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fail:
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av_free(dpds_table);
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return ret;
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}
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static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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int ret, size;
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int64_t left;
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AVStream *st;
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XWMAContext *xwma = s->priv_data;
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st = s->streams[0];
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left = xwma->data_end - avio_tell(s->pb);
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if (left <= 0) {
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return AVERROR_EOF;
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}
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/* read a single block; the default block size is 2230. */
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size = (st->codecpar->block_align > 1) ? st->codecpar->block_align : 2230;
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size = FFMIN(size, left);
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ret = av_get_packet(s->pb, pkt, size);
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if (ret < 0)
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return ret;
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pkt->stream_index = 0;
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return ret;
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}
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AVInputFormat ff_xwma_demuxer = {
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.name = "xwma",
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.long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
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.priv_data_size = sizeof(XWMAContext),
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.read_probe = xwma_probe,
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.read_header = xwma_read_header,
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.read_packet = xwma_read_packet,
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};
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