[FFmpeg-devel] [PATCH v3 2/2] avformat: add demuxer for LEGO Racers' ALP format

Paul B Mahol onemda at gmail.com
Sun Mar 8 16:31:48 EET 2020


lgtm

On 3/8/20, Zane van Iperen <zane at zanevaniperen.com> wrote:
> Signed-off-by: Zane van Iperen <zane at zanevaniperen.com>
> ---
>  Changelog                |   1 +
>  libavformat/Makefile     |   1 +
>  libavformat/allformats.c |   1 +
>  libavformat/alp.c        | 146 +++++++++++++++++++++++++++++++++++++++
>  libavformat/version.h    |   4 +-
>  5 files changed, 151 insertions(+), 2 deletions(-)
>  create mode 100644 libavformat/alp.c
>
> diff --git a/Changelog b/Changelog
> index a962657b85..41a9166827 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -44,6 +44,7 @@ version <next>:
>  - Rayman 2 APM demuxer
>  - cas video filter
>  - High Voltage Software ADPCM decoder
> +- LEGO Racers ALP (.tun & .pcm) demuxer
>
>
>  version 4.2:
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index e0681058a2..fbb29505ff 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -85,6 +85,7 @@ OBJS-$(CONFIG_AIFF_DEMUXER)              += aiffdec.o
> pcm.o isom.o \
>                                              mov_chan.o replaygain.o
>  OBJS-$(CONFIG_AIFF_MUXER)                += aiffenc.o id3v2enc.o
>  OBJS-$(CONFIG_AIX_DEMUXER)               += aixdec.o
> +OBJS-$(CONFIG_ALP_DEMUXER)               += alp.o
>  OBJS-$(CONFIG_AMR_DEMUXER)               += amr.o
>  OBJS-$(CONFIG_AMR_MUXER)                 += amr.o
>  OBJS-$(CONFIG_AMRNB_DEMUXER)             += amr.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 0209bf0e30..08012ea208 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -46,6 +46,7 @@ extern AVInputFormat  ff_afc_demuxer;
>  extern AVInputFormat  ff_aiff_demuxer;
>  extern AVOutputFormat ff_aiff_muxer;
>  extern AVInputFormat  ff_aix_demuxer;
> +extern AVInputFormat  ff_alp_demuxer;
>  extern AVInputFormat  ff_amr_demuxer;
>  extern AVOutputFormat ff_amr_muxer;
>  extern AVInputFormat  ff_amrnb_demuxer;
> diff --git a/libavformat/alp.c b/libavformat/alp.c
> new file mode 100644
> index 0000000000..c0c7905380
> --- /dev/null
> +++ b/libavformat/alp.c
> @@ -0,0 +1,146 @@
> +/*
> + * LEGO Racers ALP (.tun & .pcm) 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 "libavutil/intreadwrite.h"
> +#include "libavutil/internal.h"
> +
> +#define ALP_TAG            MKTAG('A', 'L', 'P', ' ')
> +#define ALP_MAX_READ_SIZE  4096
> +
> +typedef struct ALPHeader {
> +    uint32_t    magic;          /*< Magic Number, {'A', 'L', 'P', ' '} */
> +    uint32_t    header_size;    /*< Header size (after this). */
> +    char        adpcm[6];       /*< "ADPCM" */
> +    uint8_t     unk1;           /*< Unknown */
> +    uint8_t     num_channels;   /*< Channel Count. */
> +    uint32_t    sample_rate;    /*< Sample rate, only if header_size >= 12.
> */
> +} ALPHeader;
> +
> +static int alp_probe(const AVProbeData *p)
> +{
> +    uint32_t i;
> +
> +    if (AV_RL32(p->buf) != ALP_TAG)
> +        return 0;
> +
> +    /* Only allowed header sizes are 8 and 12. */
> +    i = AV_RL32(p->buf + 4);
> +    if (i != 8 && i != 12)
> +        return 0;
> +
> +    if (strncmp("ADPCM", p->buf + 8, 6) != 0)
> +        return 0;
> +
> +    return AVPROBE_SCORE_EXTENSION + 1;
> +}
> +
> +static int alp_read_header(AVFormatContext *s)
> +{
> +    int ret;
> +    AVStream *st;
> +    ALPHeader hdr;
> +    AVCodecParameters *par;
> +
> +    if ((hdr.magic = avio_rl32(s->pb)) != ALP_TAG)
> +        return AVERROR_INVALIDDATA;
> +
> +    hdr.header_size = avio_rl32(s->pb);
> +
> +    if (hdr.header_size != 8 && hdr.header_size != 12) {
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if ((ret = avio_read(s->pb, hdr.adpcm, sizeof(hdr.adpcm))) < 0)
> +        return ret;
> +    else if (ret != sizeof(hdr.adpcm))
> +        return AVERROR(EIO);
> +
> +    if (strncmp("ADPCM", hdr.adpcm, sizeof(hdr.adpcm)) != 0)
> +        return AVERROR_INVALIDDATA;
> +
> +    hdr.unk1                    = avio_r8(s->pb);
> +    hdr.num_channels            = avio_r8(s->pb);
> +
> +    if (hdr.header_size == 8) {
> +        /* .TUN music file */
> +        hdr.sample_rate         = 11025 * hdr.num_channels;
> +    } else {
> +        /* .PCM sound file */
> +        hdr.sample_rate         = avio_rl32(s->pb);
> +    }
> +
> +    if (hdr.sample_rate > 44100) {
> +        avpriv_request_sample(s, "Sample Rate > 44100");
> +        return AVERROR_PATCHWELCOME;
> +    }
> +
> +    if (!(st = avformat_new_stream(s, NULL)))
> +        return AVERROR(ENOMEM);
> +
> +    par                         = st->codecpar;
> +    par->codec_type             = AVMEDIA_TYPE_AUDIO;
> +    par->codec_id               = AV_CODEC_ID_ADPCM_IMA_ALP;
> +    par->format                 = AV_SAMPLE_FMT_S16;
> +    par->sample_rate            = hdr.sample_rate;
> +    par->channels               = hdr.num_channels;
> +
> +    if (hdr.num_channels == 1)
> +        par->channel_layout     = AV_CH_LAYOUT_MONO;
> +    else if (hdr.num_channels == 2)
> +        par->channel_layout     = AV_CH_LAYOUT_STEREO;
> +    else
> +        return AVERROR_INVALIDDATA;
> +
> +    par->bits_per_coded_sample  = 4;
> +    par->bits_per_raw_sample    = 16;
> +    par->block_align            = 1;
> +    par->bit_rate               = par->channels *
> +                                  par->sample_rate *
> +                                  par->bits_per_coded_sample;
> +
> +    avpriv_set_pts_info(st, 64, 1, par->sample_rate);
> +    return 0;
> +}
> +
> +static int alp_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    int ret;
> +    AVCodecParameters *par = s->streams[0]->codecpar;
> +
> +    if ((ret = av_get_packet(s->pb, pkt, ALP_MAX_READ_SIZE)) < 0)
> +        return ret;
> +
> +    pkt->flags         &= ~AV_PKT_FLAG_CORRUPT;
> +    pkt->stream_index   = 0;
> +    pkt->duration       = ret * 2 / par->channels;
> +
> +    return 0;
> +}
> +
> +AVInputFormat ff_alp_demuxer = {
> +    .name           = "alp",
> +    .long_name      = NULL_IF_CONFIG_SMALL("LEGO Racers ALP"),
> +    .read_probe     = alp_probe,
> +    .read_header    = alp_read_header,
> +    .read_packet    = alp_read_packet
> +};
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 4724269b3c..a233b67351 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -32,8 +32,8 @@
>  // 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  39
> -#define LIBAVFORMAT_VERSION_MICRO 101
> +#define LIBAVFORMAT_VERSION_MINOR  40
> +#define LIBAVFORMAT_VERSION_MICRO 100
>
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>                                                 LIBAVFORMAT_VERSION_MINOR, \
> --
> 2.17.1
>
>
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