[FFmpeg-devel] [PATCH] Add FITS Demuxer

Nicolas George george at nsup.org
Fri Jul 28 12:56:03 EEST 2017


Le decadi 10 thermidor, an CCXXV, Paras Chadha a écrit :
> Signed-off-by: Paras Chadha <paraschadha18 at gmail.com>
> ---
> 
> Made all the changes suggested.

Nice. There are a few nitpicks, but I like these versions much better.

> 
>  libavformat/Makefile     |   1 +
>  libavformat/allformats.c |   1 +
>  libavformat/fitsdec.c    | 236 +++++++++++++++++++++++++++++++++++++++++++++++
>  libavformat/version.h    |   2 +-
>  4 files changed, 239 insertions(+), 1 deletion(-)
>  create mode 100644 libavformat/fitsdec.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index b0ef82c..266b77a 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -164,6 +164,7 @@ OBJS-$(CONFIG_FFMETADATA_MUXER)          += ffmetaenc.o
>  OBJS-$(CONFIG_FIFO_MUXER)                += fifo.o
>  OBJS-$(CONFIG_FILMSTRIP_DEMUXER)         += filmstripdec.o
>  OBJS-$(CONFIG_FILMSTRIP_MUXER)           += filmstripenc.o
> +OBJS-$(CONFIG_FITS_DEMUXER)              += fitsdec.o
>  OBJS-$(CONFIG_FLAC_DEMUXER)              += flacdec.o rawdec.o \
>                                              flac_picture.o   \
>                                              oggparsevorbis.o \
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 1ebc142..3c12760 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -121,6 +121,7 @@ static void register_all(void)
>      REGISTER_MUXDEMUX(FFMETADATA,       ffmetadata);
>      REGISTER_MUXER   (FIFO,             fifo);
>      REGISTER_MUXDEMUX(FILMSTRIP,        filmstrip);
> +    REGISTER_DEMUXER (FITS,             fits);
>      REGISTER_MUXDEMUX(FLAC,             flac);
>      REGISTER_DEMUXER (FLIC,             flic);
>      REGISTER_MUXDEMUX(FLV,              flv);
> diff --git a/libavformat/fitsdec.c b/libavformat/fitsdec.c
> new file mode 100644
> index 0000000..a8e9396
> --- /dev/null
> +++ b/libavformat/fitsdec.c
> @@ -0,0 +1,236 @@
> +/*
> + * FITS demuxer
> + * Copyright (c) 2017 Paras Chadha
> + *
> + * 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
> + */
> +
> +/**
> + * @file
> + * FITS demuxer.
> + */
> +
> +#include "libavutil/intreadwrite.h"
> +#include "internal.h"
> +#include "libavutil/opt.h"
> +#include "libavcodec/fits.h"
> +#include "libavutil/bprint.h"
> +
> +#define FITS_BLOCK_SIZE 2880
> +
> +typedef struct FITSContext {
> +    const AVClass *class;
> +    AVRational framerate;
> +    int first_image;
> +    int image;
> +    int64_t pts;
> +} FITSContext;
> +
> +static int fits_probe(AVProbeData *p)
> +{
> +    const uint8_t *b = p->buf;
> +

> +    if (AV_RB64(b) == 0x53494d504c452020 &&
> +        AV_RB64(b + 8) == 0x3D20202020202020 &&
> +        AV_RB64(b + 16) == 0x2020202020202020 &&
> +        AV_RB48(b + 24) == 0x202020202054)

See Clément's comment.

> +        return AVPROBE_SCORE_MAX - 1;
> +    return 0;
> +}
> +
> +static int fits_read_header(AVFormatContext *s)
> +{
> +    AVStream *st;
> +    FITSContext * fits = s->priv_data;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> +    st->codecpar->codec_id = AV_CODEC_ID_FITS;
> +
> +    avpriv_set_pts_info(st, 64, fits->framerate.den, fits->framerate.num);
> +    fits->pts = 0;
> +    fits->first_image = 1;
> +    return 0;
> +}
> +
> +static int64_t find_size(AVFormatContext *s, FITSContext *fits, FITSHeader *header, AVBPrint *avbuf)
> +{
> +    int i, ret;
> +    char buf[FITS_BLOCK_SIZE] = { 0 };

> +    int64_t buf_size = 0, data_size = 0, t;

Maybe make them unsigned.

> +
> +    do {
> +        ret = avio_read(s->pb, buf, FITS_BLOCK_SIZE);
> +        if (ret < 0) {
> +            return ret;

> +        } else if (ret < FITS_BLOCK_SIZE) {
> +            return AVERROR_EOF;

I would say AVERROR_INVALIDDATA for truncated files.

> +        }
> +
> +        av_bprint_append_data(avbuf, buf, FITS_BLOCK_SIZE);
> +        ret = 0;
> +        buf_size = 0;
> +        while(!ret && buf_size < FITS_BLOCK_SIZE) {
> +            ret = avpriv_fits_header_parse_line(s, header, buf + buf_size, NULL);
> +            buf_size += 80;
> +        }
> +    } while (!ret);
> +    if (ret < 0)
> +        return ret;
> +
> +    fits->image = fits->first_image || header->image_extension;
> +
> +    if (header->groups) {
> +        fits->image = 0;
> +        if (header->naxis > 1)
> +            data_size = 1;
> +        for (i = 1; i < header->naxis; i++) {

> +            if(data_size && header->naxisn[i] > LLONG_MAX / data_size)

Use the correct bound, long is wrong.

> +                return AVERROR_INVALIDDATA;
> +            data_size *= header->naxisn[i];
> +        }
> +    } else if (header->naxis) {
> +        data_size = 1;
> +        for (i = 0; i < header->naxis; i++) {

> +            if(data_size && header->naxisn[i] > LLONG_MAX / data_size)

Ditto.

> +                return AVERROR_INVALIDDATA;
> +            data_size *= header->naxisn[i];
> +        }
> +    } else {
> +        fits->image = 0;
> +    }
> +
> +    if(header->pcount > LLONG_MAX - data_size)
> +        return AVERROR_INVALIDDATA;
> +    data_size += header->pcount;
> +
> +    t = (abs(header->bitpix) >> 3) * ((int64_t) header->gcount);

> +    if(data_size && t > LLONG_MAX / data_size)

Ditto.

> +        return AVERROR_INVALIDDATA;
> +    data_size *= t;
> +
> +    if (!data_size) {
> +        fits->image = 0;
> +    } else {

> +        if(2879 > LLONG_MAX - data_size)

Ditto.

> +            return AVERROR_INVALIDDATA;
> +        data_size = ((data_size + 2879) / 2880) * 2880;
> +    }
> +
> +    return data_size;
> +}
> +
> +static int fits_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    int64_t size=0, pos, ret;
> +    FITSContext *fits = s->priv_data;
> +    FITSHeader header;
> +    AVBPrint avbuf;
> +    char *buf;
> +
> +    if (fits->first_image) {
> +        avpriv_fits_header_init(&header, STATE_SIMPLE);
> +    } else {
> +        avpriv_fits_header_init(&header, STATE_XTENSION);
> +    }
> +

> +    fits->image = 0;
> +    av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
> +    size = find_size(s, fits, &header, &avbuf);
> +    fits->first_image = 0;
> +    if (size < 0) {
> +        av_bprint_finalize(&avbuf, NULL);
> +        return size;
> +    }

I think you could move this block in the loop to have all the
init/find_size logic only once.

Also, if you make sure avbuf is always inited, you could use a goto to
finalize it on error.

> +
> +    while (!fits->image) {
> +        pos = avio_skip(s->pb, size);
> +        if (pos < 0)
> +            return pos;
> +
> +        av_bprint_finalize(&avbuf, NULL);
> +        av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
> +        avpriv_fits_header_init(&header, STATE_XTENSION);
> +        size = find_size(s, fits, &header, &avbuf);
> +        if (size < 0) {
> +            av_bprint_finalize(&avbuf, NULL);
> +            return size;
> +        }
> +    }
> +
> +    if (!av_bprint_is_complete(&avbuf)) {
> +        av_bprint_finalize(&avbuf, NULL);
> +        return AVERROR(ENOMEM);
> +    }
> +
> +    // Header is sent with the first line removed...
> +    ret = av_new_packet(pkt, avbuf.len - 80 + size);
> +    if (ret < 0) {
> +        av_bprint_finalize(&avbuf, NULL);
> +        return ret;
> +    }
> +    pkt->stream_index = 0;
> +    pkt->flags |= AV_PKT_FLAG_KEY;
> +    pkt->pos = pos;
> +
> +    ret = av_bprint_finalize(&avbuf, &buf);
> +    if (ret < 0) {
> +        av_packet_unref(pkt);
> +        return ret;
> +    }
> +
> +    memcpy(pkt->data, buf + 80, avbuf.len - 80);
> +    pkt->size = avbuf.len - 80;
> +    av_freep(&buf);
> +    ret = avio_read(s->pb, pkt->data + pkt->size, size);
> +    if (ret < 0) {
> +        av_packet_unref(pkt);
> +        return ret;
> +    }
> +
> +    pkt->size += ret;
> +    pkt->pts = fits->pts;
> +    fits->pts++;
> +
> +    return 0;
> +}
> +
> +static const AVOption fits_options[] = {
> +    { "framerate", "set the framerate", offsetof(FITSContext, framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "1"}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
> +    { NULL },
> +};
> +
> +static const AVClass fits_demuxer_class = {
> +    .class_name = "FITS demuxer",
> +    .item_name  = av_default_item_name,
> +    .option     = fits_options,
> +    .version    = LIBAVUTIL_VERSION_INT,
> +};
> +
> +AVInputFormat ff_fits_demuxer = {
> +    .name           = "fits",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
> +    .priv_data_size = sizeof(FITSContext),
> +    .read_probe     = fits_probe,
> +    .read_header    = fits_read_header,
> +    .read_packet    = fits_read_packet,
> +    .priv_class     = &fits_demuxer_class,
> +    .raw_codec_id   = AV_CODEC_ID_FITS,
> +};
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 48b81f2..a8cf4c1 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  57
> -#define LIBAVFORMAT_VERSION_MINOR  76
> +#define LIBAVFORMAT_VERSION_MINOR  77
>  #define LIBAVFORMAT_VERSION_MICRO 100
> 
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

No more remarks from me, thanks for humoring my requirements.

Regards,

-- 
  Nicolas George
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