[FFmpeg-devel] [PATCH] avformat: add bitpacked demuxer

[Andreas Rheinhardt]

lance.lmwang at gmail.com:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Allows user can playback bitpacked pixel format directly:
> ffplay -video_size 1280x720 test.bitpacked
> ffplay -f bitpacked -video_size 1280x720 -pixel_format uyvy422 test.yuv
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>  libavformat/Makefile       |   1 +
>  libavformat/allformats.c   |   1 +
>  libavformat/bitpackeddec.c | 136 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 138 insertions(+)
>  create mode 100644 libavformat/bitpackeddec.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 2b5caf9..90b7333 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -138,6 +138,7 @@ OBJS-$(CONFIG_BINKA_DEMUXER)             += binka.o
>  OBJS-$(CONFIG_BINTEXT_DEMUXER)           += bintext.o sauce.o
>  OBJS-$(CONFIG_BIT_DEMUXER)               += bit.o
>  OBJS-$(CONFIG_BIT_MUXER)                 += bit.o
> +OBJS-$(CONFIG_BITPACKED_DEMUXER)         += bitpackeddec.o
>  OBJS-$(CONFIG_BMV_DEMUXER)               += bmv.o
>  OBJS-$(CONFIG_BOA_DEMUXER)               += boadec.o
>  OBJS-$(CONFIG_BFSTM_DEMUXER)             += brstm.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 1054ac9..a100639 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -96,6 +96,7 @@ extern const AVInputFormat  ff_bink_demuxer;
>  extern const AVInputFormat  ff_binka_demuxer;
>  extern const AVInputFormat  ff_bit_demuxer;
>  extern const AVOutputFormat ff_bit_muxer;
> +extern const AVInputFormat  ff_bitpacked_demuxer;
>  extern const AVInputFormat  ff_bmv_demuxer;
>  extern const AVInputFormat  ff_bfstm_demuxer;
>  extern const AVInputFormat  ff_brstm_demuxer;
> diff --git a/libavformat/bitpackeddec.c b/libavformat/bitpackeddec.c
> new file mode 100644
> index 0000000..ba404ad
> --- /dev/null
> +++ b/libavformat/bitpackeddec.c
> @@ -0,0 +1,136 @@
> +/*
> + * Raw bitpacked video demuxer
> + * Copyright (c) 2021 Limin Wang
> + *
> + * 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/imgutils.h"
> +#include "libavutil/parseutils.h"
> +#include "libavutil/pixdesc.h"
> +#include "libavutil/opt.h"
> +#include "internal.h"
> +#include "avformat.h"
> +
> +typedef struct BitPackedDemuxerContext {
> +    const AVClass *class;     /**< Class for private options. */
> +    int width, height;        /**< Integers describing video size, set by a private option. */
> +    char *pixel_format;       /**< Set by a private option. */
> +    AVRational framerate;     /**< AVRational describing framerate, set by a private option. */
> +} BitPackedDemuxerContext;
> +
> +static int bitpacked_read_header(AVFormatContext *ctx)
> +{
> +    BitPackedDemuxerContext *s = ctx->priv_data;
> +    AVStream *st;
> +    enum AVPixelFormat pix_fmt;
> +    unsigned int pgroup; /* size of the pixel group in bytes */
> +    unsigned int xinc;
> +    const AVPixFmtDescriptor *desc;
> +    int tag;
> +    int ret;
> +
> +    st = avformat_new_stream(ctx, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> +    st->codecpar->codec_id = ctx->iformat->raw_codec_id;

Seems like you copied this code from somewhere. Where did you copy it from?

> +
> +    if ((pix_fmt = av_get_pix_fmt(s->pixel_format)) == AV_PIX_FMT_NONE) {
> +        av_log(ctx, AV_LOG_ERROR, "No such pixel format: %s.\n", s->pixel_format);
> +        return AVERROR(EINVAL);
> +    }
> +    desc = av_pix_fmt_desc_get(pix_fmt);
> +
> +    ret = av_image_check_size(s->width, s->height, 0, ctx);
> +    if (ret < 0)
> +        return ret;
> +
> +    st->codecpar->width    = s->width;
> +    st->codecpar->height   = s->height;
> +    st->codecpar->format   = pix_fmt;
> +    st->codecpar->bits_per_coded_sample = av_get_bits_per_pixel(desc);
> +
> +    if (pix_fmt  == AV_PIX_FMT_YUV422P10) {
> +        tag = MKTAG('U', 'Y', 'V', 'Y');
> +        pgroup = 5;
> +        xinc   = 2;
> +    } else if (pix_fmt  == AV_PIX_FMT_UYVY422) {
> +        tag = MKTAG('U', 'Y', 'V', 'Y');
> +        pgroup = 4;
> +        xinc   = 2;
> +        pix_fmt = AV_PIX_FMT_UYVY422;
> +        st->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
> +    } else {
> +        av_log(ctx, AV_LOG_ERROR, "unsupported the pixel format: %s yet.\n",
> +               s->pixel_format);
> +        return AVERROR(EINVAL);
> +    }
> +    st->codecpar->format   = pix_fmt;
> +    st->codecpar->codec_tag = tag;
> +
> +    avpriv_set_pts_info(st, 64, s->framerate.den, s->framerate.num);
> +    ctx->packet_size  = s->width * s->height * pgroup / xinc;
> +    st->codecpar->bit_rate = av_rescale_q(ctx->packet_size,
> +                                         (AVRational){8,1}, st->time_base);
> +
> +    return 0;
> +}
> +
> +static int bitpacked_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    int ret;
> +
> +    ret = av_get_packet(s->pb, pkt, s->packet_size);
> +    pkt->pts = pkt->dts = pkt->pos / s->packet_size;
> +
> +    pkt->stream_index = 0;
> +    if (ret < 0)
> +        return ret;
> +    return 0;
> +}
> +
> +#define OFFSET(x) offsetof(BitPackedDemuxerContext, x)
> +#define DEC AV_OPT_FLAG_DECODING_PARAM
> +static const AVOption bitpacked_options[] = {
> +    { "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
> +    { "pixel_format", "set pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = "yuv422p10"}, 0, 0, DEC },
> +    { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
> +    { NULL },
> +};
> +
> +static const AVClass bitpacked_demuxer_class = {
> +    .class_name = "bitpacked demuxer",
> +    .item_name  = av_default_item_name,
> +    .option     = bitpacked_options,
> +    .version    = LIBAVUTIL_VERSION_INT,
> +};
> +
> +#if CONFIG_BITPACKED_DEMUXER
> +const AVInputFormat ff_bitpacked_demuxer = {
> +    .name           = "bitpacked",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Bitpacked"),
> +    .priv_data_size = sizeof(BitPackedDemuxerContext),
> +    .read_header    = bitpacked_read_header,
> +    .read_packet    = bitpacked_read_packet,
> +    .flags          = AVFMT_GENERIC_INDEX,
> +    .extensions     = "bitpacked",
> +    .raw_codec_id   = AV_CODEC_ID_BITPACKED,
> +    .priv_class     = &bitpacked_demuxer_class,
> +};
> +#endif // CONFIG_BITPACKED_DEMUXER
>