[FFmpeg-devel] [PATCH] OSQ lossless audio format support
Michael Niedermayer
michael at niedermayer.cc
Thu Aug 24 21:06:24 EEST 2023
On Thu, Aug 24, 2023 at 11:52:45AM +0200, Paul B Mahol wrote:
> Patches attached.
>
> Stereo decoding have some issues with some predictors so not yet bitexact.
>
> Please comment.
[...]
> diff --git a/libavformat/osq.c b/libavformat/osq.c
> new file mode 100644
> index 0000000000..36ce25313f
> --- /dev/null
> +++ b/libavformat/osq.c
> @@ -0,0 +1,117 @@
> +/*
> + * OSQ demuxer
> + * Copyright (c) 2023 Paul B Mahol
> + *
> + * 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 "libavutil/intreadwrite.h"
> +#include "avio_internal.h"
> +#include "avformat.h"
> +#include "demux.h"
> +#include "internal.h"
> +#include "rawdec.h"
> +
> +static int osq_probe(const AVProbeData *p)
> +{
> + if (AV_RL32(p->buf) != MKTAG('O','S','Q',' '))
> + return 0;
> + if (AV_RL32(p->buf + 4) != 48)
> + return 0;
> + if (AV_RL16(p->buf + 8) != 1)
> + return 0;
this can be simplified to a single memcmp() with a 10 byte array
> + if (!p->buf[10])
> + return 0;
> + if (!p->buf[11])
> + return 0;
> + if (AV_RL32(p->buf + 12) == 0)
> + return 0;
> + if (AV_RL16(p->buf + 16) == 0)
> + return 0;
inconsistant, you mix !x and == 0 for the same kind of check
> +
> + return AVPROBE_SCORE_MAX;
> +}
> +
> +static int osq_read_header(AVFormatContext *s)
> +{
> + uint32_t t, size;
> + AVStream *st;
> + int ret;
> +
> + t = avio_rl32(s->pb);
> + if (t != MKTAG('O','S','Q',' '))
> + return AVERROR_INVALIDDATA;
> +
> + size = avio_rl32(s->pb);
> + if (size != 48)
> + return AVERROR_INVALIDDATA;
> +
> + st = avformat_new_stream(s, NULL);
> + if (!st)
> + return AVERROR(ENOMEM);
> + if ((ret = ff_get_extradata(s, st->codecpar, s->pb, size)) < 0)
> + return ret;
> +
> + t = avio_rl32(s->pb);
> + if (t != MKTAG('R','I','F','F'))
> + return AVERROR_INVALIDDATA;
> + avio_skip(s->pb, 8);
> +
> + t = avio_rl32(s->pb);
> + if (t != MKTAG('f','m','t',' '))
> + return AVERROR_INVALIDDATA;
> + size = avio_rl32(s->pb);
> + avio_skip(s->pb, size);
> +
> + t = avio_rl32(s->pb);
> + size = avio_rl32(s->pb);
> + while (t != MKTAG('d','a','t','a')) {
> + avio_skip(s->pb, size);
> +
> + t = avio_rl32(s->pb);
> + size = avio_rl32(s->pb);
> + if (avio_feof(s->pb))
> + return AVERROR_INVALIDDATA;
> + }
This looks familiar, can code be shared with other RIFF based formats ?
> +
> + st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> + st->codecpar->codec_id = AV_CODEC_ID_OSQ;
> + st->codecpar->sample_rate = AV_RL32(st->codecpar->extradata + 4);
> + if (st->codecpar->sample_rate == 0)
> + return AVERROR_INVALIDDATA;
missing check for negative numbers
[...]
> diff --git a/libavcodec/osq.c b/libavcodec/osq.c
> new file mode 100644
> index 0000000000..b6dc5c1bb4
> --- /dev/null
> +++ b/libavcodec/osq.c
> @@ -0,0 +1,435 @@
> +/*
> + * OSQ audio decoder
> + * Copyright (c) 2023 Paul B Mahol
> + *
> + * 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
> + */
> +
> +#define ASSERT_LEVEL 5
that looks strange
assert level is set by the user building this, also there is no level 5
> +#include "libavutil/avassert.h"
> +#include "libavutil/internal.h"
> +#include "libavutil/intreadwrite.h"
> +#include "avcodec.h"
> +#include "codec_internal.h"
> +#include "decode.h"
> +#include "internal.h"
> +#define BITSTREAM_READER_LE
> +#include "get_bits.h"
> +#include "unary.h"
> +
> +typedef struct OSQChannel {
> + int prediction;
> + int coding_mode;
> + int residue_parameter;
> + int residue_bits;
> +} OSQChannel;
> +
> +typedef struct OSQContext {
> + GetBitContext gb;
> + OSQChannel ch[2];
> +
> + uint8_t *bitstream;
> + int64_t max_framesize;
i think the max_framesize fits in 29bits currently so 64 should not be needed
[...]
> +
> + s->bitstream = av_calloc(s->max_framesize + AV_INPUT_BUFFER_PADDING_SIZE, sizeof(*s->bitstream));
> + if (!s->bitstream)
> + return AVERROR(ENOMEM);
> +
> + for (int ch = 0; ch < avctx->ch_layout.nb_channels; ch++) {
> + s->decode_buffer[ch] = av_calloc(s->frame_samples + 4,
> + sizeof(*s->decode_buffer[ch]));
> + if (!s->decode_buffer[ch])
> + return AVERROR(ENOMEM);
> + }
> +
> + s->pkt = avctx->internal->in_pkt;
> +
> + return 0;
> +}
> +
> +static uint32_t get_urice(GetBitContext *gb, int k)
> +{
> + uint32_t z, x, b;
> +
> + x = get_unary(gb, 1, 512);
> + b = get_bits_long(gb, k & 31);
> + z = b | x << (k & 31);
the k & 31 seems unneeded
[...]
> + }
> + break;
> + case AV_SAMPLE_FMT_S32P:
> + for (int ch = 0; ch < avctx->ch_layout.nb_channels; ch++) {
> + int32_t *dst = (int32_t *)frame->extended_data[ch];
> + int32_t *src = s->decode_buffer[ch] + 4;
> +
> + for (int n = 0; n < frame->nb_samples; n++)
> + dst[n] = src[n];
memcpy() unless these can overlap
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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