[FFmpeg-devel] [PATCH 3/3] ffprobe: add JSON output printing format.
Stefano Sabatini
stefano.sabatini-lala at poste.it
Tue Sep 6 15:52:00 CEST 2011
On date Saturday 2011-09-03 20:12:56 +0200, Clément Bœsch encoded:
> ---
> doc/ffprobe.texi | 4 ++
> ffprobe.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 120 insertions(+), 4 deletions(-)
>
> diff --git a/doc/ffprobe.texi b/doc/ffprobe.texi
> index 6f7e83b..b66c619 100644
> --- a/doc/ffprobe.texi
> +++ b/doc/ffprobe.texi
> @@ -87,6 +87,10 @@ Use sexagesimal format HH:MM:SS.MICROSECONDS for time values.
> Prettify the format of the displayed values, it corresponds to the
> options "-unit -prefix -byte_binary_prefix -sexagesimal".
>
> + at item -print_format
@item -print_format @var{format}
> +Set the output printing format.
> +Current available formats are "default" and "json"
> +
> @item -show_format
> Show information about the container format of the input multimedia
> stream.
> diff --git a/ffprobe.c b/ffprobe.c
> index ce2b505..f2a461f 100644
> --- a/ffprobe.c
> +++ b/ffprobe.c
> @@ -131,6 +131,8 @@ struct writer {
> const char *items_sep; ///< separator between sets of key/value couples
> const char *section_sep; ///< separator between sections (streams, packets, ...)
> const char *header, *footer;
> + void (*print_section_start)(const char *, int);
> + void (*print_section_end) (const char *, int);
> void (*print_header)(const char *);
> void (*print_footer)(const char *);
> void (*print_int_f)(const char *, int);
> @@ -139,6 +141,83 @@ struct writer {
> };
>
>
> +/* JSON output */
> +
> +static void json_print_header(const char *section)
> +{
> + printf("{\n");
> +}
> +
> +static char *json_escape_str(const char *s)
> +{
> + static const char json_escape[] = {'"', '\\', '\b', '\f', '\n', '\r', '\t', 0};
> + static const char json_subst[] = {'"', '\\', 'b', 'f', 'n', 'r', 't', 0};
> + char *ret, *p;
> + int i, len = 0;
> +
> + for (i = 0; s[i]; i++) {
> + if (strchr(json_escape, s[i])) len += 2;
> + else if ((unsigned char)s[i] < 32) len += 6;
maybe you can pass an unsigned char string, and avoid the obufscating
casts, a note on the line of // handle non-printable chars
may help.
> + else len += 1;
> + }
maybe add a comment header: // compute the length of the escaped string
> +
> + p = ret = av_malloc(len + 1);
> + if (!p)
> + return NULL;
> + for (i = 0; s[i]; i++) {
> + char *q = strchr(json_escape, s[i]);
> + if (q) {
> + *p++ = '\\';
> + *p++ = json_subst[q - json_escape];
> + } else if ((unsigned char)s[i] < 32) {
> + snprintf(p, 7, "\\u00%02x", s[i] & 0xff);
why & 0xff?
> + p += 6;
> + } else {
> + *p++ = s[i];
> + }
> + }
> + *p = 0;
> + return ret;
> +}
> +
> +static void json_print_str(const char *key, const char *value)
> +{
> + char *key_esc = json_escape_str(key);
> + char *value_esc = json_escape_str(value);
> + printf(" \"%s\": \"%s\"",
> + key_esc ? key_esc : "",
> + value_esc ? value_esc : "");
> + av_free(key_esc);
> + av_free(value_esc);
> +}
> +
> +static void json_print_int(const char *key, int value)
> +{
> + char *key_esc = json_escape_str(key);
> + printf(" \"%s\": %d", key_esc ? key_esc : "", value);
> + av_free(key_esc);
> +}
> +
> +static void json_print_footer(const char *section)
> +{
> + printf("\n }");
> +}
> +
> +static void json_print_section_start(const char *section, int multiple_entries)
> +{
> + char *section_esc = json_escape_str(section);
> + printf("\n \"%s\":%s", section_esc ? section_esc : "",
> + multiple_entries ? " [" : " ");
> + av_free(section_esc);
> +}
> +
> +static void json_print_section_end(const char *section, int multiple_entries)
> +{
> + if (multiple_entries)
> + printf("]");
> +}
> +
> +
> /* Default output */
>
> static void default_print_header(const char *section)
> @@ -220,6 +299,24 @@ static void show_packets(struct writer *w, AVFormatContext *fmt_ctx)
> show_packet(w, fmt_ctx, &pkt, i++);
> }
>
> +static void json_show_tags(struct writer *w, AVDictionary *dict)
> +{
> + AVDictionaryEntry *tag = NULL;
> + int first = 1;
> + if (!dict)
> + return;
> + printf(",\n \"tags\": {\n");
> + while ((tag = av_dict_get(dict, "", tag, AV_DICT_IGNORE_SUFFIX))) {
> + if (first) {
> + print_str0(tag->key, tag->value);
> + first = 0;
> + } else {
> + print_str(tag->key, tag->value);
> + }
> + }
> + printf("\n }");
> +}
> +
> static void default_show_tags(struct writer *w, AVDictionary *dict)
> {
> AVDictionaryEntry *tag = NULL;
> @@ -387,6 +484,16 @@ static struct writer writers[] = {{
> .section_sep = "\n",
> .footer = "\n",
> WRITER_FUNC(default),
> + },{
> + .name = "json",
> + .header = "{",
> + .item_sep = ",\n",
> + .items_sep = ",",
> + .section_sep = ",",
> + .footer = "\n}\n",
> + .print_section_start = json_print_section_start,
> + .print_section_end = json_print_section_end,
> + WRITER_FUNC(json),
> }
> };
>
> @@ -401,9 +508,13 @@ static int get_writer(const char *name)
> return -1;
> }
>
> -#define SECTION_PRINT(name, left) do { \
> +#define SECTION_PRINT(name, multiple_entries, left) do { \
> if (do_show_ ## name) { \
> + if (w->print_section_start) \
> + w->print_section_start(#name, multiple_entries); \
> show_ ## name (w, fmt_ctx); \
> + if (w->print_section_end) \
> + w->print_section_end(#name, multiple_entries); \
> if (left) \
> printf("%s", w->section_sep); \
> } \
> @@ -428,9 +539,9 @@ static int probe_file(const char *filename)
> if (w->header)
> printf("%s", w->header);
>
> - SECTION_PRINT(packets, do_show_streams || do_show_format);
> - SECTION_PRINT(streams, do_show_format);
> - SECTION_PRINT(format, 0);
> + SECTION_PRINT(packets, 1, do_show_streams || do_show_format);
> + SECTION_PRINT(streams, 1, do_show_format);
> + SECTION_PRINT(format, 0, 0);
>
> if (w->footer)
> printf("%s", w->footer);
> @@ -500,6 +611,7 @@ static const OptionDef options[] = {
> "use sexagesimal format HOURS:MM:SS.MICROSECONDS for time units" },
> { "pretty", 0, {(void*)&opt_pretty},
> "prettify the format of displayed values, make it more human readable" },
> + { "print_format", OPT_STRING | HAS_ARG, {(void*)&print_format}, "Set the output printing format. Available formats: default, json" },
Nit: for consistency just "set the output printing format (available formats are: default, json)
> { "show_format", OPT_BOOL, {(void*)&do_show_format} , "show format/container info" },
> { "show_packets", OPT_BOOL, {(void*)&do_show_packets}, "show packets info" },
> { "show_streams", OPT_BOOL, {(void*)&do_show_streams}, "show streams info" },
> --
> 1.7.6.1
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Looks fine otherwise.
--
FFmpeg = Fantastic and Faithless Mythic Portable Elastic God
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