[FFmpeg-devel] [PATCH] lavc/bsf: add a showinfo filter

[Andreas Rheinhardt]

Anton Khirnov:
> Analogous to the (a)showinfo lavfi filters, logs basic packet
> information. Mainly useful for debugging/testing/development.
> ---
>  Changelog                      |  1 +
>  doc/bitstream_filters.texi     |  4 +++
>  libavcodec/bitstream_filters.c |  1 +
>  libavcodec/bsf/Makefile        |  1 +
>  libavcodec/bsf/showinfo.c      | 66 ++++++++++++++++++++++++++++++++++
>  5 files changed, 73 insertions(+)
>  create mode 100644 libavcodec/bsf/showinfo.c
> 
> diff --git a/Changelog b/Changelog
> index c1fd66b4bd..c5fb21d198 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -23,6 +23,7 @@ version <next>:
>  - ffmpeg CLI -bsf option may now be used for input as well as output
>  - ffmpeg CLI options may now be used as -/opt <path>, which is equivalent
>    to -opt <contents of file <path>>
> +- showinfo bitstream filter
>  
>  version 6.1:
>  - libaribcaption decoder
> diff --git a/doc/bitstream_filters.texi b/doc/bitstream_filters.texi
> index dc4f85bac0..d5bac105ff 100644
> --- a/doc/bitstream_filters.texi
> +++ b/doc/bitstream_filters.texi
> @@ -887,6 +887,10 @@ For example, to set PTS equal to DTS (not recommended if B-frames are involved):
>  ffmpeg -i INPUT -c:a copy -bsf:a setts=pts=DTS out.mkv
>  @end example
>  
> + at section showinfo
> +Log basic packet information. Mainly useful for testing, debugging,
> +and development.
> +
>  @anchor{text2movsub}
>  @section text2movsub
>  
> diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
> index 1e9a676a3d..1bae113d92 100644
> --- a/libavcodec/bitstream_filters.c
> +++ b/libavcodec/bitstream_filters.c
> @@ -58,6 +58,7 @@ extern const FFBitStreamFilter ff_pgs_frame_merge_bsf;
>  extern const FFBitStreamFilter ff_prores_metadata_bsf;
>  extern const FFBitStreamFilter ff_remove_extradata_bsf;
>  extern const FFBitStreamFilter ff_setts_bsf;
> +extern const FFBitStreamFilter ff_showinfo_bsf;
>  extern const FFBitStreamFilter ff_text2movsub_bsf;
>  extern const FFBitStreamFilter ff_trace_headers_bsf;
>  extern const FFBitStreamFilter ff_truehd_core_bsf;
> diff --git a/libavcodec/bsf/Makefile b/libavcodec/bsf/Makefile
> index 7831b0f2aa..62609eb24e 100644
> --- a/libavcodec/bsf/Makefile
> +++ b/libavcodec/bsf/Makefile
> @@ -36,6 +36,7 @@ OBJS-$(CONFIG_PGS_FRAME_MERGE_BSF)        += bsf/pgs_frame_merge.o
>  OBJS-$(CONFIG_PRORES_METADATA_BSF)        += bsf/prores_metadata.o
>  OBJS-$(CONFIG_REMOVE_EXTRADATA_BSF)       += bsf/remove_extradata.o
>  OBJS-$(CONFIG_SETTS_BSF)                  += bsf/setts.o
> +OBJS-$(CONFIG_SHOWINFO_BSF)               += bsf/showinfo.o
>  OBJS-$(CONFIG_TEXT2MOVSUB_BSF)            += bsf/movsub.o
>  OBJS-$(CONFIG_TRACE_HEADERS_BSF)          += bsf/trace_headers.o
>  OBJS-$(CONFIG_TRUEHD_CORE_BSF)            += bsf/truehd_core.o
> diff --git a/libavcodec/bsf/showinfo.c b/libavcodec/bsf/showinfo.c
> new file mode 100644
> index 0000000000..dc1ac8ceb6
> --- /dev/null
> +++ b/libavcodec/bsf/showinfo.c
> @@ -0,0 +1,66 @@
> +/*
> + * Copyright (c) 2024 Anton Khirnov <anton at khirnov.net>
> + *
> + * 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 <stdint.h>

You should use inttypes.h instead -- it provides everything stdint.h
provides and the print directive defines like PRId64.

> +
> +#include "bsf.h"
> +#include "bsf_internal.h"
> +
> +#include "libavutil/log.h"
> +#include "libavutil/timestamp.h"
> +
> +typedef struct ShowinfoContext {
> +    uint64_t nb_packets;
> +} ShowinfoContext;
> +
> +static int showinfo_filter(AVBSFContext *ctx, AVPacket *pkt)
> +{
> +    ShowinfoContext *priv = ctx->priv_data;
> +
> +    while (1) {

This loop will only ever be executed once and should be removed.

> +        int ret;
> +
> +        ret = ff_bsf_get_packet_ref(ctx, pkt);
> +        if (ret < 0)
> +            return ret;
> +
> +        av_log(ctx, AV_LOG_INFO,
> +               "n:%7"PRIu64" "
> +               "size:%7d "
> +               "pts:%s pt:%s "
> +               "dts:%s dt:%s "
> +               "ds:%"PRId64" d:%s "
> +               "\n",
> +               priv->nb_packets, pkt->size,
> +               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &ctx->time_base_in),
> +               av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &ctx->time_base_in),
> +               pkt->duration, av_ts2timestr(pkt->duration, &ctx->time_base_in));
> +
> +        priv->nb_packets++;
> +
> +        return 0;
> +    }
> +}
> +
> +const FFBitStreamFilter ff_showinfo_bsf = {
> +    .p.name         = "showinfo",
> +    .filter         = showinfo_filter,
> +    .priv_data_size = sizeof(ShowinfoContext),
> +};