[FFmpeg-devel] [PATCH 2/2] avformat: add HCOM demuxer

James Almer jamrial at gmail.com
Wed Jan 16 04:52:50 EET 2019


On 1/2/2019 3:53 PM, Paul B Mahol wrote:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavformat/Makefile     |  1 +
>  libavformat/allformats.c |  1 +
>  libavformat/hcom.c       | 89 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 91 insertions(+)
>  create mode 100644 libavformat/hcom.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index c42ceb40c5..c010fc83f9 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -219,6 +219,7 @@ OBJS-$(CONFIG_H263_MUXER)                += rawenc.o
>  OBJS-$(CONFIG_H264_DEMUXER)              += h264dec.o rawdec.o
>  OBJS-$(CONFIG_H264_MUXER)                += rawenc.o
>  OBJS-$(CONFIG_HASH_MUXER)                += hashenc.o
> +OBJS-$(CONFIG_HCOM_DEMUXER)              += hcom.o
>  OBJS-$(CONFIG_HDS_MUXER)                 += hdsenc.o
>  OBJS-$(CONFIG_HEVC_DEMUXER)              += hevcdec.o rawdec.o
>  OBJS-$(CONFIG_HEVC_MUXER)                += rawenc.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 399625fd78..06844986f3 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -176,6 +176,7 @@ extern AVOutputFormat ff_h263_muxer;
>  extern AVInputFormat  ff_h264_demuxer;
>  extern AVOutputFormat ff_h264_muxer;
>  extern AVOutputFormat ff_hash_muxer;
> +extern AVInputFormat  ff_hcom_demuxer;
>  extern AVOutputFormat ff_hds_muxer;
>  extern AVInputFormat  ff_hevc_demuxer;
>  extern AVOutputFormat ff_hevc_muxer;
> diff --git a/libavformat/hcom.c b/libavformat/hcom.c
> new file mode 100644
> index 0000000000..933ecce373
> --- /dev/null
> +++ b/libavformat/hcom.c
> @@ -0,0 +1,89 @@
> +/*
> + * HCOM demuxer
> + * Copyright (c) 2019 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 "libavcodec/internal.h"
> +#include "avformat.h"
> +#include "internal.h"
> +#include "pcm.h"
> +
> +static int hcom_probe(AVProbeData *p)
> +{
> +    if (!memcmp(p->buf+65, "FSSD", 4) &&
> +        !memcmp(p->buf+128, "HCOM", 4))

You should check that p->buf_size is at least 132.

> +        return AVPROBE_SCORE_MAX;
> +    return 0;
> +}
> +
> +static int hcom_read_header(AVFormatContext *s)
> +{
> +    AVStream *st;
> +    unsigned data_size, rsrc_size, huffcount;
> +    unsigned compresstype, divisor;
> +    unsigned dict_entries;
> +    int ret;
> +
> +    avio_skip(s->pb, 83);
> +    data_size = avio_rb32(s->pb);
> +    rsrc_size = avio_rb32(s->pb);
> +    avio_skip(s->pb, 128-91+4);
> +    huffcount = avio_rb32(s->pb);

Unused?

> +    avio_skip(s->pb, 4);
> +    compresstype = avio_rb32(s->pb);
> +    if (compresstype > 1)
> +        return AVERROR_INVALIDDATA;

Is it invalid data, or just unknown/unsupported? If the latter, make the
return value AVERROR_PATCHWELCOME and maybe request a sample.

> +    divisor = avio_rb32(s->pb);
> +    if (divisor == 0 || divisor > 4)
> +        return AVERROR_INVALIDDATA;
> +    dict_entries = avio_rb16(s->pb);
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;
> +    st->codecpar->channels    = 1;
> +    st->codecpar->sample_rate = 22050 / divisor;
> +    st->codecpar->codec_id    = AV_CODEC_ID_HCOM;
> +    st->codecpar->bits_per_coded_sample = 8;
> +    st->codecpar->block_align = 4;
> +
> +    ret = ff_alloc_extradata(st->codecpar, dict_entries * 4 + 7);
> +    if (ret < 0)
> +        return ret;
> +    AV_WB16(st->codecpar->extradata, dict_entries);
> +    AV_WB32(st->codecpar->extradata + 2, compresstype);
> +    avio_read(s->pb, st->codecpar->extradata + 6, dict_entries * 4);
> +    avio_skip(s->pb, 1);
> +    st->codecpar->extradata[dict_entries * 4 + 6] = avio_r8(s->pb);
> +
> +    avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
> +
> +    return 0;
> +}
> +
> +AVInputFormat ff_hcom_demuxer = {
> +    .name           = "hcom",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Macintosh HCOM"),
> +    .read_probe     = hcom_probe,
> +    .read_header    = hcom_read_header,
> +    .read_packet    = ff_pcm_read_packet,
> +};
> 



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