yading@11: /*
yading@11:  * xWMA demuxer
yading@11:  * Copyright (c) 2011 Max Horn
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include <inttypes.h>
yading@11: 
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: #include "riff.h"
yading@11: 
yading@11: /*
yading@11:  * Demuxer for xWMA, a Microsoft audio container used by XAudio 2.
yading@11:  */
yading@11: 
yading@11: typedef struct {
yading@11:     int64_t data_end;
yading@11: } XWMAContext;
yading@11: 
yading@11: static int xwma_probe(AVProbeData *p)
yading@11: {
yading@11:     if (!memcmp(p->buf, "RIFF", 4) && !memcmp(p->buf + 8, "XWMA", 4))
yading@11:         return AVPROBE_SCORE_MAX;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int xwma_read_header(AVFormatContext *s)
yading@11: {
yading@11:     int64_t size;
yading@11:     int ret;
yading@11:     uint32_t dpds_table_size = 0;
yading@11:     uint32_t *dpds_table = 0;
yading@11:     unsigned int tag;
yading@11:     AVIOContext *pb = s->pb;
yading@11:     AVStream *st;
yading@11:     XWMAContext *xwma = s->priv_data;
yading@11:     int i;
yading@11: 
yading@11:     /* The following code is mostly copied from wav.c, with some
yading@11:      * minor alterations.
yading@11:      */
yading@11: 
yading@11:     /* check RIFF header */
yading@11:     tag = avio_rl32(pb);
yading@11:     if (tag != MKTAG('R', 'I', 'F', 'F'))
yading@11:         return -1;
yading@11:     avio_rl32(pb); /* file size */
yading@11:     tag = avio_rl32(pb);
yading@11:     if (tag != MKTAG('X', 'W', 'M', 'A'))
yading@11:         return -1;
yading@11: 
yading@11:     /* parse fmt header */
yading@11:     tag = avio_rl32(pb);
yading@11:     if (tag != MKTAG('f', 'm', 't', ' '))
yading@11:         return -1;
yading@11:     size = avio_rl32(pb);
yading@11:     st = avformat_new_stream(s, NULL);
yading@11:     if (!st)
yading@11:         return AVERROR(ENOMEM);
yading@11: 
yading@11:     ret = ff_get_wav_header(pb, st->codec, size);
yading@11:     if (ret < 0)
yading@11:         return ret;
yading@11:     st->need_parsing = AVSTREAM_PARSE_NONE;
yading@11: 
yading@11:     /* All xWMA files I have seen contained WMAv2 data. If there are files
yading@11:      * using WMA Pro or some other codec, then we need to figure out the right
yading@11:      * extradata for that. Thus, ask the user for feedback, but try to go on
yading@11:      * anyway.
yading@11:      */
yading@11:     if (st->codec->codec_id != AV_CODEC_ID_WMAV2) {
yading@11:         avpriv_request_sample(s, "Unexpected codec (tag 0x04%x; id %d)",
yading@11:                               st->codec->codec_tag, st->codec->codec_id);
yading@11:     } else {
yading@11:         /* In all xWMA files I have seen, there is no extradata. But the WMA
yading@11:          * codecs require extradata, so we provide our own fake extradata.
yading@11:          *
yading@11:          * First, check that there really was no extradata in the header. If
yading@11:          * there was, then try to use it, after asking the user to provide a
yading@11:          * sample of this unusual file.
yading@11:          */
yading@11:         if (st->codec->extradata_size != 0) {
yading@11:             /* Surprise, surprise: We *did* get some extradata. No idea
yading@11:              * if it will work, but just go on and try it, after asking
yading@11:              * the user for a sample.
yading@11:              */
yading@11:             avpriv_request_sample(s, "Unexpected extradata (%d bytes)",
yading@11:                                   st->codec->extradata_size);
yading@11:         } else {
yading@11:             st->codec->extradata_size = 6;
yading@11:             st->codec->extradata      = av_mallocz(6 + FF_INPUT_BUFFER_PADDING_SIZE);
yading@11:             if (!st->codec->extradata)
yading@11:                 return AVERROR(ENOMEM);
yading@11: 
yading@11:             /* setup extradata with our experimentally obtained value */
yading@11:             st->codec->extradata[4] = 31;
yading@11:         }
yading@11:     }
yading@11: 
yading@11:     if (!st->codec->channels) {
yading@11:         av_log(s, AV_LOG_WARNING, "Invalid channel count: %d\n",
yading@11:                st->codec->channels);
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     }
yading@11:     if (!st->codec->bits_per_coded_sample) {
yading@11:         av_log(s, AV_LOG_WARNING, "Invalid bits_per_coded_sample: %d\n",
yading@11:                st->codec->bits_per_coded_sample);
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     }
yading@11: 
yading@11:     /* set the sample rate */
yading@11:     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
yading@11: 
yading@11:     /* parse the remaining RIFF chunks */
yading@11:     for (;;) {
yading@11:         if (pb->eof_reached)
yading@11:             return -1;
yading@11:         /* read next chunk tag */
yading@11:         tag = avio_rl32(pb);
yading@11:         size = avio_rl32(pb);
yading@11:         if (tag == MKTAG('d', 'a', 't', 'a')) {
yading@11:             /* We assume that the data chunk comes last. */
yading@11:             break;
yading@11:         } else if (tag == MKTAG('d','p','d','s')) {
yading@11:             /* Quoting the MSDN xWMA docs on the dpds chunk: "Contains the
yading@11:              * decoded packet cumulative data size array, each element is the
yading@11:              * number of bytes accumulated after the corresponding xWMA packet
yading@11:              * is decoded in order."
yading@11:              *
yading@11:              * Each packet has size equal to st->codec->block_align, which in
yading@11:              * all cases I saw so far was always 2230. Thus, we can use the
yading@11:              * dpds data to compute a seeking index.
yading@11:              */
yading@11: 
yading@11:             /* Error out if there is more than one dpds chunk. */
yading@11:             if (dpds_table) {
yading@11:                 av_log(s, AV_LOG_ERROR, "two dpds chunks present\n");
yading@11:                 return -1;
yading@11:             }
yading@11: 
yading@11:             /* Compute the number of entries in the dpds chunk. */
yading@11:             if (size & 3) {  /* Size should be divisible by four */
yading@11:                 av_log(s, AV_LOG_WARNING,
yading@11:                        "dpds chunk size %"PRId64" not divisible by 4\n", size);
yading@11:             }
yading@11:             dpds_table_size = size / 4;
yading@11:             if (dpds_table_size == 0 || dpds_table_size >= INT_MAX / 4) {
yading@11:                 av_log(s, AV_LOG_ERROR,
yading@11:                        "dpds chunk size %"PRId64" invalid\n", size);
yading@11:                 return -1;
yading@11:             }
yading@11: 
yading@11:             /* Allocate some temporary storage to keep the dpds data around.
yading@11:              * for processing later on.
yading@11:              */
yading@11:             dpds_table = av_malloc(dpds_table_size * sizeof(uint32_t));
yading@11:             if (!dpds_table) {
yading@11:                 return AVERROR(ENOMEM);
yading@11:             }
yading@11: 
yading@11:             for (i = 0; i < dpds_table_size; ++i) {
yading@11:                 dpds_table[i] = avio_rl32(pb);
yading@11:                 size -= 4;
yading@11:             }
yading@11:         }
yading@11:         avio_skip(pb, size);
yading@11:     }
yading@11: 
yading@11:     /* Determine overall data length */
yading@11:     if (size < 0)
yading@11:         return -1;
yading@11:     if (!size) {
yading@11:         xwma->data_end = INT64_MAX;
yading@11:     } else
yading@11:         xwma->data_end = avio_tell(pb) + size;
yading@11: 
yading@11: 
yading@11:     if (dpds_table && dpds_table_size) {
yading@11:         int64_t cur_pos;
yading@11:         const uint32_t bytes_per_sample
yading@11:                 = (st->codec->channels * st->codec->bits_per_coded_sample) >> 3;
yading@11: 
yading@11:         /* Estimate the duration from the total number of output bytes. */
yading@11:         const uint64_t total_decoded_bytes = dpds_table[dpds_table_size - 1];
yading@11: 
yading@11:         if(!bytes_per_sample) {
yading@11:             av_log(s, AV_LOG_ERROR, "bytes_per_sample is 0\n");
yading@11:             return AVERROR_INVALIDDATA;
yading@11:         }
yading@11: 
yading@11:         st->duration = total_decoded_bytes / bytes_per_sample;
yading@11: 
yading@11:         /* Use the dpds data to build a seek table.  We can only do this after
yading@11:          * we know the offset to the data chunk, as we need that to determine
yading@11:          * the actual offset to each input block.
yading@11:          * Note: If we allowed ourselves to assume that the data chunk always
yading@11:          * follows immediately after the dpds block, we could of course guess
yading@11:          * the data block's start offset already while reading the dpds chunk.
yading@11:          * I decided against that, just in case other chunks ever are
yading@11:          * discovered.
yading@11:          */
yading@11:         cur_pos = avio_tell(pb);
yading@11:         for (i = 0; i < dpds_table_size; ++i) {
yading@11:             /* From the number of output bytes that would accumulate in the
yading@11:              * output buffer after decoding the first (i+1) packets, we compute
yading@11:              * an offset / timestamp pair.
yading@11:              */
yading@11:             av_add_index_entry(st,
yading@11:                                cur_pos + (i+1) * st->codec->block_align, /* pos */
yading@11:                                dpds_table[i] / bytes_per_sample,         /* timestamp */
yading@11:                                st->codec->block_align,                   /* size */
yading@11:                                0,                                        /* duration */
yading@11:                                AVINDEX_KEYFRAME);
yading@11:         }
yading@11:     } else if (st->codec->bit_rate) {
yading@11:         /* No dpds chunk was present (or only an empty one), so estimate
yading@11:          * the total duration using the average bits per sample and the
yading@11:          * total data length.
yading@11:          */
yading@11:         st->duration = (size<<3) * st->codec->sample_rate / st->codec->bit_rate;
yading@11:     }
yading@11: 
yading@11:     av_free(dpds_table);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int xwma_read_packet(AVFormatContext *s, AVPacket *pkt)
yading@11: {
yading@11:     int ret, size;
yading@11:     int64_t left;
yading@11:     AVStream *st;
yading@11:     XWMAContext *xwma = s->priv_data;
yading@11: 
yading@11:     st = s->streams[0];
yading@11: 
yading@11:     left = xwma->data_end - avio_tell(s->pb);
yading@11:     if (left <= 0) {
yading@11:         return AVERROR_EOF;
yading@11:     }
yading@11: 
yading@11:     /* read a single block; the default block size is 2230. */
yading@11:     size = (st->codec->block_align > 1) ? st->codec->block_align : 2230;
yading@11:     size = FFMIN(size, left);
yading@11: 
yading@11:     ret  = av_get_packet(s->pb, pkt, size);
yading@11:     if (ret < 0)
yading@11:         return ret;
yading@11: 
yading@11:     pkt->stream_index = 0;
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: AVInputFormat ff_xwma_demuxer = {
yading@11:     .name           = "xwma",
yading@11:     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft xWMA"),
yading@11:     .priv_data_size = sizeof(XWMAContext),
yading@11:     .read_probe     = xwma_probe,
yading@11:     .read_header    = xwma_read_header,
yading@11:     .read_packet    = xwma_read_packet,
yading@11: };