Am 05.03.2020 um 01:40 schrieb Zane van Iperen:
> Signed-off-by: Zane van Iperen <z...@zanevaniperen.com>
> ---
> libavformat/Makefile | 1 +
> libavformat/allformats.c | 1 +
> libavformat/alp.c | 135 +++++++++++++++++++++++++++++++++++++++
> libavformat/version.h | 4 +-
> 4 files changed, 139 insertions(+), 2 deletions(-)
> create mode 100644 libavformat/alp.c
>
> 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..76703e7ad1
> --- /dev/null
> +++ b/libavformat/alp.c
> @@ -0,0 +1,135 @@
> +/*
> + * LEGO Racers ALP (.tun & .pcm) demuxer
> + *
> + * Copyright (C) 2020 Zane van Iperen (z...@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"
> +
> +#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)
> +{
> + if (AV_RL32(p->buf) != ALP_TAG)
> + return 0;
> +
> + if (AV_RL32(p->buf) < 8)
This check must be wrong, because you already know that the left side
here is ALP_TAG. Did you mean AV_RL32(p->buf + 4)? If so, you should
explicitly check for it being 8 or 12 (because otherwise the demuxer
would just return AVERROR_INVALIDDATA).
And why haven't you added a check based upon the "ADPCM" magic word?
> + return 0;
> +
> + return AVPROBE_SCORE_EXTENSION + 1;
> +}
> +
> +static int alp_read_header(AVFormatContext *s)
> +{
> + int ret;
> + AVStream *st;
> + ALPHeader hdr;
> + AVCodecParameters *par;
> +
> + memset(&hdr, 0, sizeof(hdr));
You actually set every field you use before you use it, so this is
unnecessary.
> +
> + if (!(st = avformat_new_stream(s, NULL)))
This could be moved down below so that you avoid allocating an
AVStream if you error out later.
> + return AVERROR(ENOMEM);
> +
> + 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 you don't add a check for this, the multiplication for the bit_rate
below can overflow and par->sample_rate can end up negative.
> + }
> +
> + 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;
Why don't you align on the '='?
> + pkt->stream_index = 0;
> + pkt->duration = ret * (8 / par->bits_per_coded_sample) /
> par->channels;
If par->bits_per_coded_sample is always four, you could hardcode this
here.
- Andreas
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