On 2017-04-15 17:56, James Almer wrote: > On 4/15/2017 10:36 AM, James Darnley wrote: >> --- >> libavformat/Makefile | 1 + >> libavformat/allformats.c | 1 + >> libavformat/falcom_xa.c | 98 >> ++++++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 100 insertions(+) >> create mode 100644 libavformat/falcom_xa.c > > Changelog/version.h/etc before you push.
Sure.
>>
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index 6bdfbe6789..06b6b5da57 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -158,6 +158,7 @@ OBJS-$(CONFIG_EA_DEMUXER) +=
>> electronicarts.o
>> OBJS-$(CONFIG_EAC3_DEMUXER) += ac3dec.o rawdec.o
>> OBJS-$(CONFIG_EAC3_MUXER) += rawenc.o
>> OBJS-$(CONFIG_EPAF_DEMUXER) += epafdec.o pcm.o
>> +OBJS-$(CONFIG_FALCOM_XA_DEMUXER) += falcom_xa.o
>> OBJS-$(CONFIG_FFM_DEMUXER) += ffmdec.o
>> OBJS-$(CONFIG_FFM_MUXER) += ffmenc.o
>> OBJS-$(CONFIG_FFMETADATA_DEMUXER) += ffmetadec.o
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 09e62c3cfc..0c23ea9df0 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -117,6 +117,7 @@ static void register_all(void)
>> REGISTER_MUXDEMUX(EAC3, eac3);
>> REGISTER_DEMUXER (EPAF, epaf);
>> REGISTER_MUXER (F4V, f4v);
>> + REGISTER_DEMUXER (FALCOM_XA, falcom_xa);
>
> Maybe just Xanadu?
>
>> REGISTER_MUXDEMUX(FFM, ffm);
>> REGISTER_MUXDEMUX(FFMETADATA, ffmetadata);
>> REGISTER_MUXER (FIFO, fifo);
>> diff --git a/libavformat/falcom_xa.c b/libavformat/falcom_xa.c
>> new file mode 100644
>> index 0000000000..4c5f32a1b6
>> --- /dev/null
>> +++ b/libavformat/falcom_xa.c
>> @@ -0,0 +1,98 @@
>> +/*
>> + * Falcom Xanadu demuxer
>> + * Copyright (c) 2016 James Darnley
>
> 2017?
I wrote it in November 2016 and have only just remembered about it.
>> + *
>> + * 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 "avformat.h"
>> +
>> +typedef struct FalcomXADemuxContext {
>> + const AVClass *class;
>> + unsigned frame_size;
>> +} FalcomXADemuxContext;
>> +
>> +static av_cold
>> +int falcom_xa_read_header(AVFormatContext *s)
>
> A probe function should be added if possible.
>
>> +{
>> + int sample_rate, bit_depth, channels;
>> + AVStream *st;
>> + AVIOContext *pb = s->pb;
>> +
>> + avio_seek(pb, 22, SEEK_SET);
>
> avio_skip() is more in line with most demuxers.
>
> What are those first 22 bytes? I assume header magic (which you should
> check in a probe function) and maybe some version byte?
> If the latter, better check it here.
It is a riff or wave header with incorrect data. I can probe for the
commonalities for all the files but I couldn't be bothered at the time.
>> + channels = avio_rl16(pb);
>> + if (channels != 2)
>> + return AVERROR_INVALIDDATA;
>
> If there are real world files with more than two channels, you could
> instead return PATCHWELCOME and even ask for a sample.
I wonder. I only wanted it to decode the 24 files from the game.
>> +
>> + sample_rate = avio_rl32(pb);
>> + if (sample_rate != 44100)
>> + return AVERROR_INVALIDDATA;
>
> Same.
>
>> +
>> + avio_seek(pb, 34, SEEK_SET);
>
> avio_skip().
>
>> + bit_depth = avio_rl16(pb);
>> + if (bit_depth != 16)
>> + return AVERROR_INVALIDDATA;
>> +
>> + avio_seek(pb, 44, SEEK_SET);
>
> Same.
All noted.
>> +
>> + st = avformat_new_stream(s, NULL);
>> + if (!st)
>> + return AVERROR(ENOMEM);
>> +
>> + st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
>> + st->codecpar->codec_id = AV_CODEC_ID_ADPCM_MS;
>> + st->codecpar->sample_rate = sample_rate;
>> + st->codecpar->channels = channels;
>> + st->codecpar->block_align = 2048;
>> +
>> + return 0;
>> +}
>> +
>> +static
>> +int falcom_xa_read_packet(AVFormatContext *s, AVPacket *pkt)
>> +{
>> + FalcomXADemuxContext *ctx = s->priv_data;
>> +
>> + if (ctx->frame_size == 0) {
>> + unsigned tell = avio_tell(s->pb);
>
> avio_tell() returns int64_t.
I know but none of the files are larger than 12 MiB.
>> + unsigned size = avio_rl32(s->pb);
>> + av_log(ctx, AV_LOG_DEBUG, "read size %u (0x%x) at offset %u
>> (0x%x)\n",
>> + size, size, tell, tell);
>> + if (size % 2048)
>
> Nit: size & 2047.
Also noted.
>> + return AVERROR_INVALIDDATA;
>> + ctx->frame_size = size;
>> + avio_skip(s->pb, 4); // unknown bytes
>> + }
>> +
>> + ctx->frame_size -= 2048;
>> + return av_get_packet(s->pb, pkt, 2048);
>> +}
>> +
>> +static const AVClass falcom_xa_demux_class = {
>> + .class_name = "Falcom Xanadu demuxer",
>> + .item_name = av_default_item_name,
>> + .version = LIBAVUTIL_VERSION_INT,
>> +};
>> +
>> +AVInputFormat ff_falcom_xa_demuxer = {
>> + .name = "falcom_xa",
>> + .long_name = NULL_IF_CONFIG_SMALL("Falcom Xanadu demuxer"),
>> + .priv_data_size = sizeof(FalcomXADemuxContext),
>> + .read_header = falcom_xa_read_header,
>> + .read_packet = falcom_xa_read_packet,
>> + .priv_class = &falcom_xa_demux_class,
>
> No known extension/s? And did you try using AVFMT_GENERIC_INDEX flag
> to see if it enables seeking without a custom read_seek() function?
The files are all .dec so I guess I could add that at the least. And
I'll try the seeking.
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