[FFmpeg-devel] [PATCH] ffprobe: add -select_streams option

[Clément Bœsch]

On Thu, Oct 04, 2012 at 05:40:44PM +0200, Stefano Sabatini wrote:
> NIT: would -specify_streams be a better name?
> 

As said on IRC, I prefer the -select_streams as it is in the current patch
since "specify" sounds wrong: you're not asking ffprobe to specify
anything. "filter" or "pick" might work, but "select" really is OK IMO.

> TODO: add Changelog entry
> ---
>  doc/ffprobe.texi |   15 +++++++++++++++
>  ffprobe.c        |   29 +++++++++++++++++++++++++++--
>  2 files changed, 42 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/ffprobe.texi b/doc/ffprobe.texi
> index 58ea383..ee69fbf 100644
> --- a/doc/ffprobe.texi
> +++ b/doc/ffprobe.texi
> @@ -94,6 +94,21 @@ For example for printing the output in JSON format, specify:
>  For more details on the available output printing formats, see the
>  Writers section below.
>  
> + at item -select_streams @var{stream_specifier}
> +Select only the streams specified by @var{stream_specifier}. This
> +option affect only the options related to streams

affects?

> +(e.g. @code{show_streams}, @code{show_packets}, etc.).
> +
> +For example to show only audio streams, you can use the command:
> + at example
> +ffprobe -show_streams -select_streams a INPUT
> + at end example
> +
> +To show only video packets belonging to the video stream with index 1:
> + at example
> +ffprobe -show_packets -select_streams v:1 INPUT
> + at end example
> +
>  @item -show_data
>  Show payload data, as an hexadecimal and ASCII dump. Coupled with
>  @option{-show_packets}, it will dump the packets' data. Coupled with
> diff --git a/ffprobe.c b/ffprobe.c
> index 4fb4982..c8a9022 100644
> --- a/ffprobe.c
> +++ b/ffprobe.c
> @@ -69,6 +69,7 @@ static int use_value_sexagesimal_format = 0;
>  static int show_private_data            = 1;
>  
>  static char *print_format;
> +static char *stream_specifier;
>  
>  /* section structure definition */
>  
> @@ -138,8 +139,10 @@ static const char unit_second_str[]         = "s"    ;
>  static const char unit_hertz_str[]          = "Hz"   ;
>  static const char unit_byte_str[]           = "byte" ;
>  static const char unit_bit_per_second_str[] = "bit/s";
> +
>  static uint64_t *nb_streams_packets;
>  static uint64_t *nb_streams_frames;
> +static int *selected_streams;
>  
>  static void exit_program(void)
>  {
> @@ -1614,6 +1617,8 @@ static void read_packets(WriterContext *w, AVFormatContext *fmt_ctx)
>      av_init_packet(&pkt);
>  
>      while (!av_read_frame(fmt_ctx, &pkt)) {
> +        if (!selected_streams[pkt.stream_index])
> +            continue;

Isn't av_free_packet() still needed?

>          if (do_read_packets) {
>              if (do_show_packets)
>                  show_packet(w, fmt_ctx, &pkt, i++);
> @@ -1789,7 +1794,8 @@ static void show_streams(WriterContext *w, AVFormatContext *fmt_ctx)
>      int i;
>      writer_print_section_header(w, SECTION_ID_STREAMS);
>      for (i = 0; i < fmt_ctx->nb_streams; i++)
> -        show_stream(w, fmt_ctx, i);
> +        if (selected_streams[i])
> +            show_stream(w, fmt_ctx, i);
>      writer_print_section_footer(w);
>  }
>  
> @@ -1896,7 +1902,7 @@ static void close_input_file(AVFormatContext **ctx_ptr)
>  static int probe_file(WriterContext *wctx, const char *filename)
>  {
>      AVFormatContext *fmt_ctx;
> -    int ret;
> +    int ret, i;
>      int section_id;
>  
>      do_read_frames = do_show_frames || do_count_frames;
> @@ -1906,6 +1912,22 @@ static int probe_file(WriterContext *wctx, const char *filename)
>      if (ret >= 0) {
>          nb_streams_frames  = av_calloc(fmt_ctx->nb_streams, sizeof(*nb_streams_frames));
>          nb_streams_packets = av_calloc(fmt_ctx->nb_streams, sizeof(*nb_streams_packets));
> +        selected_streams   = av_calloc(fmt_ctx->nb_streams, sizeof(*selected_streams));
> +
> +        for (i = 0; i < fmt_ctx->nb_streams; i++) {
> +            if (stream_specifier) {
> +                ret = avformat_match_stream_specifier(fmt_ctx,
> +                                                      fmt_ctx->streams[i],
> +                                                      stream_specifier);
> +                if (ret < 0)
> +                    goto end;
> +                else
> +                    selected_streams[i] = ret;
> +            } else {
> +                selected_streams[i] = 1;
> +            }
> +        }
> +
>          if (do_read_frames || do_read_packets) {
>              if (do_show_frames && do_show_packets &&
>                  wctx->writer->flags & WRITER_FLAG_PUT_PACKETS_AND_FRAMES_IN_SAME_CHAPTER)
> @@ -1925,9 +1947,11 @@ static int probe_file(WriterContext *wctx, const char *filename)
>          if (do_show_format)
>              show_format(wctx, fmt_ctx);
>  
> +    end:
>          close_input_file(&fmt_ctx);
>          av_freep(&nb_streams_frames);
>          av_freep(&nb_streams_packets);
> +        av_freep(&selected_streams);
>      }
>      return ret;
>  }
> @@ -2062,6 +2086,7 @@ static const OptionDef real_options[] = {
>      { "print_format", OPT_STRING | HAS_ARG, {(void*)&print_format},
>        "set the output printing format (available formats are: default, compact, csv, flat, ini, json, xml)", "format" },
>      { "of", OPT_STRING | HAS_ARG, {(void*)&print_format}, "alias for -print_format", "format" },
> +    { "select_streams", OPT_STRING | HAS_ARG, {(void*)&stream_specifier}, "select the specified streams", "stream_specifier" },
>      { "show_data",    OPT_BOOL, {(void*)&do_show_data}, "show packets data" },
>      { "show_error",   OPT_BOOL, {(void*)&do_show_error} ,  "show probing error" },
>      { "show_format",  OPT_BOOL, {&do_show_format} , "show format/container info" },

Rest looks OK.

In a perfect world we would even have a FATE test (or maybe you're looking
for using the feature in some particular already existing tests?).

-- 
Clément B.
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