| /* |
| * xWMA demuxer |
| * Copyright (c) 2011 Max Horn |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include <inttypes.h> |
| #include <stdint.h> |
| |
| #include "avformat.h" |
| #include "internal.h" |
| #include "riff.h" |
| |
| /* |
| * Demuxer for xWMA, a Microsoft audio container used by XAudio 2. |
| */ |
| |
| typedef struct XWMAContext { |
| int64_t data_end; |
| } XWMAContext; |
| |
| static int xwma_probe(AVProbeData *p) |
| { |
| if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4)) |
| return AVPROBE_SCORE_MAX; |
| return 0; |
| } |
| |
| static int xwma_read_header(AVFormatContext *s) |
| { |
| int64_t size; |
| int ret = 0; |
| uint32_t dpds_table_size = 0; |
| uint32_t *dpds_table = NULL; |
| unsigned int tag; |
| AVIOContext *pb = s->pb; |
| AVStream *st; |
| XWMAContext *xwma = s->priv_data; |
| int i; |
| |
| /* The following code is mostly copied from wav.c, with some |
| * minor alterations. |
| */ |
| |
| /* check RIFF header */ |
| tag = avio_rl32(pb); |
| if (tag != MKTAG('R', 'I', 'F', 'F')) |
| return -1; |
| avio_rl32(pb); /* file size */ |
| tag = avio_rl32(pb); |
| if (tag != MKTAG('X', 'W', 'M', 'A')) |
| return -1; |
| |
| /* parse fmt header */ |
| tag = avio_rl32(pb); |
| if (tag != MKTAG('f', 'm', 't', ' ')) |
| return -1; |
| size = avio_rl32(pb); |
| st = avformat_new_stream(s, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| |
| ret = ff_get_wav_header(s, pb, st->codec, size, 0); |
| if (ret < 0) |
| return ret; |
| st->need_parsing = AVSTREAM_PARSE_NONE; |
| |
| /* All xWMA files I have seen contained WMAv2 data. If there are files |
| * using WMA Pro or some other codec, then we need to figure out the right |
| * extradata for that. Thus, ask the user for feedback, but try to go on |
| * anyway. |
| */ |
| if (st->codec->codec_id != AV_CODEC_ID_WMAV2 && |
| st->codec->codec_id != AV_CODEC_ID_WMAPRO) { |
| avpriv_request_sample(s, "Unexpected codec (tag 0x04%x; id %d)", |
| st->codec->codec_tag, st->codec->codec_id); |
| } else { |
| /* In all xWMA files I have seen, there is no extradata. But the WMA |
| * codecs require extradata, so we provide our own fake extradata. |
| * |
| * First, check that there really was no extradata in the header. If |
| * there was, then try to use it, after asking the user to provide a |
| * sample of this unusual file. |
| */ |
| if (st->codec->extradata_size != 0) { |
| /* Surprise, surprise: We *did* get some extradata. No idea |
| * if it will work, but just go on and try it, after asking |
| * the user for a sample. |
| */ |
| avpriv_request_sample(s, "Unexpected extradata (%d bytes)", |
| st->codec->extradata_size); |
| } else if (st->codec->codec_id == AV_CODEC_ID_WMAPRO) { |
| if (ff_alloc_extradata(st->codec, 18)) |
| return AVERROR(ENOMEM); |
| |
| memset(st->codec->extradata, 0, st->codec->extradata_size); |
| st->codec->extradata[ 0] = st->codec->bits_per_coded_sample; |
| st->codec->extradata[14] = 224; |
| } else { |
| if (ff_alloc_extradata(st->codec, 6)) |
| return AVERROR(ENOMEM); |
| |
| memset(st->codec->extradata, 0, st->codec->extradata_size); |
| /* setup extradata with our experimentally obtained value */ |
| st->codec->extradata[4] = 31; |
| } |
| } |
| |
| if (!st->codec->channels) { |
| av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n", |
| st->codec->channels); |
| return AVERROR_INVALIDDATA; |
| } |
| if (!st->codec->bits_per_coded_sample) { |
| av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n", |
| st->codec->bits_per_coded_sample); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* set the sample rate */ |
| avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate); |
| |
| /* parse the remaining RIFF chunks */ |
| for (;;) { |
| if (pb->eof_reached) { |
| ret = AVERROR_EOF; |
| goto fail; |
| } |
| /* read next chunk tag */ |
| tag = avio_rl32(pb); |
| size = avio_rl32(pb); |
| if (tag == MKTAG('d', 'a', 't', 'a')) { |
| /* We assume that the data chunk comes last. */ |
| break; |
| } else if (tag == MKTAG('d','p','d','s')) { |
| /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the |
| * decoded packet cumulative data size array, each element is the |
| * number of bytes accumulated after the corresponding xWMA packet |
| * is decoded in order." |
| * |
| * Each packet has size equal to st->codec->block_align, which in |
| * all cases I saw so far was always 2230. Thus, we can use the |
| * dpds data to compute a seeking index. |
| */ |
| |
| /* Error out if there is more than one dpds chunk. */ |
| if (dpds_table) { |
| av_log(s, AV_LOG_ERROR, "two dpds chunks present\n"); |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| |
| /* Compute the number of entries in the dpds chunk. */ |
| if (size & 3) { /* Size should be divisible by four */ |
| av_log(s, AV_LOG_WARNING, |
| "dpds chunk size %"PRId64" not divisible by 4\n", size); |
| } |
| dpds_table_size = size / 4; |
| if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) { |
| av_log(s, AV_LOG_ERROR, |
| "dpds chunk size %"PRId64" invalid\n", size); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| /* Allocate some temporary storage to keep the dpds data around. |
| * for processing later on. |
| */ |
| dpds_table = av_malloc_array(dpds_table_size, sizeof(uint32_t)); |
| if (!dpds_table) { |
| return AVERROR(ENOMEM); |
| } |
| |
| for (i = 0; i < dpds_table_size; ++i) { |
| dpds_table[i] = avio_rl32(pb); |
| size -= 4; |
| } |
| } |
| avio_skip(pb, size); |
| } |
| |
| /* Determine overall data length */ |
| if (size < 0) { |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| if (!size) { |
| xwma->data_end = INT64_MAX; |
| } else |
| xwma->data_end = avio_tell(pb) + size; |
| |
| |
| if (dpds_table && dpds_table_size) { |
| int64_t cur_pos; |
| const uint32_t bytes_per_sample |
| = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3; |
| |
| /* Estimate the duration from the total number of output bytes. */ |
| const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1]; |
| |
| if (!bytes_per_sample) { |
| av_log(s, AV_LOG_ERROR, |
| "Invalid bits_per_coded_sample %d for %d channels\n", |
| st->codec->bits_per_coded_sample, st->codec->channels); |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| |
| st->duration = total_decoded_bytes / bytes_per_sample; |
| |
| /* Use the dpds data to build a seek table. We can only do this after |
| * we know the offset to the data chunk, as we need that to determine |
| * the actual offset to each input block. |
| * Note: If we allowed ourselves to assume that the data chunk always |
| * follows immediately after the dpds block, we could of course guess |
| * the data block's start offset already while reading the dpds chunk. |
| * I decided against that, just in case other chunks ever are |
| * discovered. |
| */ |
| cur_pos = avio_tell(pb); |
| for (i = 0; i < dpds_table_size; ++i) { |
| /* From the number of output bytes that would accumulate in the |
| * output buffer after decoding the first (i+1) packets, we compute |
| * an offset / timestamp pair. |
| */ |
| av_add_index_entry(st, |
| cur_pos + (i+1) * st->codec->block_align, /* pos */ |
| dpds_table[i] / bytes_per_sample, /* timestamp */ |
| st->codec->block_align, /* size */ |
| 0, /* duration */ |
| AVINDEX_KEYFRAME); |
| } |
| } else if (st->codec->bit_rate) { |
| /* No dpds chunk was present (or only an empty one), so estimate |
| * the total duration using the average bits per sample and the |
| * total data length. |
| */ |
| st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate; |
| } |
| |
| fail: |
| av_free(dpds_table); |
| |
| return ret; |
| } |
| |
| static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| int ret, size; |
| int64_t left; |
| AVStream *st; |
| XWMAContext *xwma = s->priv_data; |
| |
| st = s->streams[0]; |
| |
| left = xwma->data_end - avio_tell(s->pb); |
| if (left <= 0) { |
| return AVERROR_EOF; |
| } |
| |
| /* read a single block; the default block size is 2230. */ |
| size = (st->codec->block_align > 1) ? st->codec->block_align : 2230; |
| size = FFMIN(size, left); |
| |
| ret = av_get_packet(s->pb, pkt, size); |
| if (ret < 0) |
| return ret; |
| |
| pkt->stream_index = 0; |
| return ret; |
| } |
| |
| AVInputFormat ff_xwma_demuxer = { |
| .name = "xwma", |
| .long_name = NULL_IF_CONFIG_SMALL("Microsoft xWMA"), |
| .priv_data_size = sizeof(XWMAContext), |
| .read_probe = xwma_probe, |
| .read_header = xwma_read_header, |
| .read_packet = xwma_read_packet, |
| }; |
