[FFmpeg-devel] [PATCH 2/2] avformat: add demuxer for Rayman 2's APM format
Zane van Iperen
zane at zanevaniperen.com
Mon Feb 17 11:49:52 EET 2020
On 17/2/20 7:26 pm, Paul B Mahol wrote:
>
> On 2/17/20, Zane van Iperen <zane at zanevaniperen.com> wrote:
>> Adds support for the APM file format used by Ubisoft's Rayman 2.
>>
>> Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>
>> ---
>> libavformat/Makefile | 1 +
>> libavformat/allformats.c | 1 +
>> libavformat/apm.c | 171 +++++++++++++++++++++++++++++++++++++++
>> libavformat/version.h | 2 +-
>> 4 files changed, 174 insertions(+), 1 deletion(-)
>> create mode 100644 libavformat/apm.c
>>
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index a9972fd99a..e0681058a2 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -92,6 +92,7 @@ OBJS-$(CONFIG_AMRWB_DEMUXER) += amr.o
>> OBJS-$(CONFIG_ANM_DEMUXER) += anm.o
>> OBJS-$(CONFIG_APC_DEMUXER) += apc.o
>> OBJS-$(CONFIG_APE_DEMUXER) += ape.o apetag.o img2.o
>> +OBJS-$(CONFIG_APM_DEMUXER) += apm.o
>> OBJS-$(CONFIG_APNG_DEMUXER) += apngdec.o
>> OBJS-$(CONFIG_APNG_MUXER) += apngenc.o
>> OBJS-$(CONFIG_APTX_DEMUXER) += aptxdec.o rawdec.o
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 3ea4100e85..0209bf0e30 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -53,6 +53,7 @@ extern AVInputFormat ff_amrwb_demuxer;
>> extern AVInputFormat ff_anm_demuxer;
>> extern AVInputFormat ff_apc_demuxer;
>> extern AVInputFormat ff_ape_demuxer;
>> +extern AVInputFormat ff_apm_demuxer;
>> extern AVInputFormat ff_apng_demuxer;
>> extern AVOutputFormat ff_apng_muxer;
>> extern AVInputFormat ff_aptx_demuxer;
>> diff --git a/libavformat/apm.c b/libavformat/apm.c
>> new file mode 100644
>> index 0000000000..d13c2eda31
>> --- /dev/null
>> +++ b/libavformat/apm.c
>> @@ -0,0 +1,171 @@
>> +/*
>> + * Rayman 2 APM Demuxer
>> + *
>> + * Copyright (C) 2020 Zane van Iperen (zane at zanevaniperen.com)
>> + *
>> + * 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"
>> +#include "internal.h"
>> +#include "riff.h"
>> +#include "libavutil/internal.h"
>> +#include "libavutil/intreadwrite.h"
>> +
>> +#define APM_FILE_HEADER_SIZE 20
>> +#define APM_VS12_CHUNK_SIZE 76
>> +#define APM_MAX_READ_SIZE 4096
>> +
>> +typedef struct APMState {
>> + int32_t has_saved;
>> + int32_t predictor_r;
>> + int32_t step_index_r;
>> + int32_t saved_r;
>> + int32_t predictor_l;
>> + int32_t step_index_l;
>> + int32_t saved_l;
>> +} APMState;
>> +
>> +typedef struct APMVS12Chunk {
>> + uint32_t magic;
>> + uint32_t file_size;
>> + uint32_t data_size;
>> + uint32_t unk1;
>> + uint32_t unk2;
>> + APMState state;
>> + uint32_t pad[7];
>> +} APMVS12Chunk;
>> +
>> +static void apm_parse_vs12(APMVS12Chunk *vs12, const uint8_t *buf)
>> +{
>> + vs12->magic = AV_RL32(buf + 0);
>> + vs12->file_size = AV_RL32(buf + 4);
>> + vs12->data_size = AV_RL32(buf + 8);
>> + vs12->unk1 = AV_RL32(buf + 12);
>> + vs12->unk2 = AV_RL32(buf + 16);
>> +
>> + vs12->state.has_saved = AV_RL32(buf + 20);
>> + vs12->state.predictor_r = AV_RL32(buf + 24);
>> + vs12->state.step_index_r = AV_RL32(buf + 28);
>> + vs12->state.saved_r = AV_RL32(buf + 32);
>> + vs12->state.predictor_l = AV_RL32(buf + 36);
>> + vs12->state.step_index_l = AV_RL32(buf + 40);
>> + vs12->state.saved_l = AV_RL32(buf + 44);
>> +
>> + for (int i = 0; i < FF_ARRAY_ELEMS(vs12->pad); i++)
>> + vs12->pad[i] = AV_RL32(buf + 48 + (i * 4));
>> +}
>> +
>> +static int apm_read_header(AVFormatContext *s)
>> +{
>> + int64_t ret;
>> + AVStream *st;
>> + APMVS12Chunk vs12;
>> + uint8_t buf[APM_VS12_CHUNK_SIZE];
>> +
>> + if (!(st = avformat_new_stream(s, NULL)))
>> + return AVERROR(ENOMEM);
>> +
>> + /* The header starts with a WAVEFORMATEX */
>> + if ((ret = ff_get_wav_header(s, s->pb, st->codecpar,
>> APM_FILE_HEADER_SIZE, 0)) < 0)
>> + return ret;
>> +
>> + if (st->codecpar->bits_per_coded_sample != 4)
>> + return AVERROR_INVALIDDATA;
>> +
>> + if (st->codecpar->codec_tag != 0x2000)
>> + return AVERROR_INVALIDDATA;
>> +
>> + /* ff_get_wav_header() does most of the work, but we need to fix a few
>> things. */
>> + st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APM;
>> + st->codecpar->codec_tag = 0;
>> +
>> + if (st->codecpar->channels == 2)
>> + st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
>> + else if (st->codecpar->channels == 1)
>> + st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
>> + else
>> + return AVERROR_INVALIDDATA;
>> +
>> + st->codecpar->format = AV_SAMPLE_FMT_S16P;
>> + st->codecpar->bits_per_raw_sample = 16;
>> + st->codecpar->bit_rate = st->codecpar->channels *
>> + st->codecpar->sample_rate *
>> +
>> st->codecpar->bits_per_coded_sample;
>> +
>> + if ((ret = avio_read(s->pb, buf, APM_VS12_CHUNK_SIZE)) < 0)
>> + return ret;
>> + else if (ret != APM_VS12_CHUNK_SIZE)
>> + return AVERROR(EIO);
>> +
>> + apm_parse_vs12(&vs12, buf);
>> +
>> + if (vs12.magic != MKTAG('v', 's', '1', '2')) {
>> + return AVERROR_INVALIDDATA;
>> + }
>> +
>> + if (vs12.state.has_saved) {
>> + avpriv_request_sample(s, "Saved Samples");
>> + return AVERROR_PATCHWELCOME;
>> + }
>> +
>> + if (avio_rl32(s->pb) != MKTAG('D', 'A', 'T', 'A'))
>> + return AVERROR_INVALIDDATA;
>> +
>> + if ((ret = ff_alloc_extradata(st->codecpar, 16)) < 0)
>> + return ret;
>> +
>> + AV_WN32(st->codecpar->extradata + 0, vs12.state.predictor_l);
>> + AV_WN32(st->codecpar->extradata + 4, vs12.state.step_index_l);
>> + AV_WN32(st->codecpar->extradata + 8, vs12.state.predictor_r);
>> + AV_WN32(st->codecpar->extradata + 12, vs12.state.step_index_r);
>
> Use same endianess as it is written in file.
>
Fixed (and in the codec too).
>> +
>> + avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
>> + st->start_time = 0;
>> + st->duration = vs12.data_size *
>> + (8 / st->codecpar->bits_per_coded_sample) /
>> + st->codecpar->channels;
>> + return 0;
>> +}
>> +
>> +static int apm_read_packet(AVFormatContext *s, AVPacket *pkt)
>> +{
>> + int ret;
>> + AVCodecParameters *par = s->streams[0]->codecpar;
>> +
>> + /*
>> + * For future reference: if files with the `has_saved` field set ever
>> + * surface, `saved_l`, and `saved_r` will each contain 8 "saved"
>> samples
>> + * that should be sent to the decoder before the actual data.
>> + */
>> +
>> + if ((ret = av_get_packet(s->pb, pkt, APM_MAX_READ_SIZE)) < 0)
>> + return ret;
>> +
>> + pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
>> + pkt->stream_index = 0;
>> + pkt->duration = ret * (8 / par->bits_per_coded_sample) /
>> par->channels;
>> +
>> + return 0;
>> +}
>> +
>> +AVInputFormat ff_apm_demuxer = {
>> + .name = "apm",
>> + .long_name = NULL_IF_CONFIG_SMALL("Ubisoft Rayman 2 APM"),
>> + .read_header = apm_read_header,
>> + .read_packet = apm_read_packet,
>> + .extensions = "apm"
>
> Also add probe function.
There's no real "magic" fields to look for, hence why I set the `extensions`
field. What would a probe function do in this case?
>
>> +};
>> diff --git a/libavformat/version.h b/libavformat/version.h
>> index 94fa57614d..4724269b3c 100644
>> --- a/libavformat/version.h
>> +++ b/libavformat/version.h
>> @@ -32,7 +32,7 @@
>> // Major bumping may affect Ticket5467, 5421, 5451(compatibility with
>> Chromium)
>> // Also please add any ticket numbers that you believe might be affected
>> here
>> #define LIBAVFORMAT_VERSION_MAJOR 58
>> -#define LIBAVFORMAT_VERSION_MINOR 38
>> +#define LIBAVFORMAT_VERSION_MINOR 39
>> #define LIBAVFORMAT_VERSION_MICRO 101
>
> Reset micro to 0, when changing minor.
>
>
Gah, knew I'd forgotten something simple. Fixed.
>>
>> #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>> --
>> 2.17.1
>>
>>
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Zane
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