[FFmpeg-devel] [PATCH 08/11] fftools/opt_common: switch to avcodec_get_supported_config()
Niklas Haas
ffmpeg at haasn.xyz
Sat Apr 6 14:38:57 EEST 2024
On Fri, 05 Apr 2024 16:36:50 -0300 James Almer <jamrial at gmail.com> wrote:
> On 4/5/2024 3:57 PM, Niklas Haas wrote:
> > From: Niklas Haas <git at haasn.dev>
> >
> > While rewriting this macro, I decided to make it a bit more flexible so
> > it can work for all of the fields (including future fields) in a more
> > generic way.
> > ---
> > fftools/opt_common.c | 86 ++++++++++++++++++++++----------------------
> > 1 file changed, 43 insertions(+), 43 deletions(-)
> >
> > diff --git a/fftools/opt_common.c b/fftools/opt_common.c
> > index 947a226d8d1..1bf66580192 100644
> > --- a/fftools/opt_common.c
> > +++ b/fftools/opt_common.c
> > @@ -262,22 +262,32 @@ int show_buildconf(void *optctx, const char *opt, const char *arg)
> > return 0;
> > }
> >
> > -#define PRINT_CODEC_SUPPORTED(codec, field, type, list_name, term, get_name) \
> > - if (codec->field) { \
> > - const type *p = codec->field; \
> > - \
> > - printf(" Supported " list_name ":"); \
> > - while (*p != term) { \
> > - get_name(*p); \
> > - printf(" %s", name); \
> > - p++; \
> > - } \
> > - printf("\n"); \
> > - } \
> > +#define PRINT_CODEC_SUPPORTED(codec, config, type, name, elem, cond, fmt, ...) \
> > + do { \
> > + const type *elem = NULL; \
> > + avcodec_get_supported_config(NULL, codec, config, 0, \
> > + (const void **) &elem); \
> > + if (elem) { \
> > + printf(" Supported " name ":"); \
> > + while (cond) { \
> > + printf(" " fmt, __VA_ARGS__); \
> > + elem++; \
> > + } \
> > + printf("\n"); \
> > + } \
> > + } while (0)
> > +
> > +static char *get_channel_layout_desc(const AVChannelLayout *layout,
> > + char desc[], int desc_size)
> > +{
> > + av_channel_layout_describe(layout, desc, desc_size);
> > + return desc;
> > +}
> >
> > static void print_codec(const AVCodec *c)
> > {
> > int encoder = av_codec_is_encoder(c);
> > + char desc[128];
> >
> > printf("%s %s [%s]:\n", encoder ? "Encoder" : "Decoder", c->name,
> > c->long_name ? c->long_name : "");
> > @@ -343,35 +353,19 @@ static void print_codec(const AVCodec *c)
> > printf("\n");
> > }
> >
> > - if (c->supported_framerates) {
> > - const AVRational *fps = c->supported_framerates;
> > -
> > - printf(" Supported framerates:");
> > - while (fps->num) {
> > - printf(" %d/%d", fps->num, fps->den);
> > - fps++;
> > - }
> > - printf("\n");
> > - }
> > - PRINT_CODEC_SUPPORTED(c, pix_fmts, enum AVPixelFormat, "pixel formats",
> > - AV_PIX_FMT_NONE, GET_PIX_FMT_NAME);
> > - PRINT_CODEC_SUPPORTED(c, supported_samplerates, int, "sample rates", 0,
> > - GET_SAMPLE_RATE_NAME);
> > - PRINT_CODEC_SUPPORTED(c, sample_fmts, enum AVSampleFormat, "sample formats",
> > - AV_SAMPLE_FMT_NONE, GET_SAMPLE_FMT_NAME);
> > -
> > - if (c->ch_layouts) {
> > - const AVChannelLayout *p = c->ch_layouts;
> > -
> > - printf(" Supported channel layouts:");
> > - while (p->nb_channels) {
> > - char name[128];
> > - av_channel_layout_describe(p, name, sizeof(name));
> > - printf(" %s", name);
> > - p++;
> > - }
> > - printf("\n");
> > - }
> > + PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_FRAME_RATE, AVRational, "framerates",
> > + fps, fps->num, "%d/%d", fps->num, fps->den);
> > + PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_PIX_FORMAT, enum AVPixelFormat,
> > + "pixel formats", fmt, *fmt != AV_PIX_FMT_NONE,
> > + "%s", av_get_pix_fmt_name(*fmt));
> > + PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_SAMPLE_RATE, int, "sample rates",
> > + rate, *rate != 0, "%d", *rate);
> > + PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_SAMPLE_FORMAT, enum AVSampleFormat,
> > + "sample formats", fmt, *fmt != AV_SAMPLE_FMT_NONE,
> > + "%s", av_get_sample_fmt_name(*fmt));
> > + PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_CHANNEL_LAYOUT, AVChannelLayout,
> > + "channel layouts", layout, layout->nb_channels,
> > + "%s", get_channel_layout_desc(layout, desc, sizeof(desc)));
>
> Since you're rewriting everything, might as well go and port this to
> AVBprint, so we're not limited to 128 bytes for the channel layout.
> You can use av_bprintf() to write to the buffer using the different
> specifiers, then printf() the final bprint buffer to stdout.
I implemented something like this initially, but it is IMO premature
optimization as there is no multi-threading going on in this code, so no
risk of colliding printf() calls. printf() already internally buffers
data, so we are not gaining anything by buffering it inside an AVBPrint
a second time.
That said, using an AVBPrint instead of a fixed size buffer is a good
idea for the channel layout specifically, something like this:
diff --git a/fftools/opt_common.c b/fftools/opt_common.c
index 1bf66580192..fae68949f89 100644
--- a/fftools/opt_common.c
+++ b/fftools/opt_common.c
@@ -277,17 +277,17 @@ int show_buildconf(void *optctx, const char *opt, const char *arg)
} \
} while (0)
-static char *get_channel_layout_desc(const AVChannelLayout *layout,
- char desc[], int desc_size)
+static char *get_channel_layout_desc(const AVChannelLayout *layout, AVBPrint *bp)
{
- av_channel_layout_describe(layout, desc, desc_size);
- return desc;
+ av_bprint_clear(bp);
+ av_channel_layout_describe_bprintf(layout, bp);
+ return bp->str;
}
static void print_codec(const AVCodec *c)
{
int encoder = av_codec_is_encoder(c);
- char desc[128];
+ AVBPrint desc;
printf("%s %s [%s]:\n", encoder ? "Encoder" : "Decoder", c->name,
c->long_name ? c->long_name : "");
@@ -363,9 +363,12 @@ static void print_codec(const AVCodec *c)
PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_SAMPLE_FORMAT, enum AVSampleFormat,
"sample formats", fmt, *fmt != AV_SAMPLE_FMT_NONE,
"%s", av_get_sample_fmt_name(*fmt));
+
+ av_bprint_init(&desc, AV_BPRINT_SIZE_AUTOMATIC);
PRINT_CODEC_SUPPORTED(c, AV_CODEC_CONFIG_CHANNEL_LAYOUT, AVChannelLayout,
"channel layouts", layout, layout->nb_channels,
- "%s", get_channel_layout_desc(layout, desc, sizeof(desc)));
+ "%s", get_channel_layout_desc(layout, &desc));
+ av_bprint_finalize(&desc, NULL);
if (c->priv_class) {
show_help_children(c->priv_class,
>
> >
> > if (c->priv_class) {
> > show_help_children(c->priv_class,
> > @@ -566,8 +560,14 @@ static void show_help_bsf(const char *name)
> > }
> >
> > printf("Bit stream filter %s\n", bsf->name);
> > - PRINT_CODEC_SUPPORTED(bsf, codec_ids, enum AVCodecID, "codecs",
> > - AV_CODEC_ID_NONE, GET_CODEC_NAME);
> > + if (bsf->codec_ids) {
> > + const enum AVCodecID *id = bsf->codec_ids;
> > + printf(" Supported codecs:");
> > + while (*id != AV_CODEC_ID_NONE) {
> > + printf(" %s", avcodec_descriptor_get(*id)->name);
> > + id++;
> > + }
> > + }
> > if (bsf->priv_class)
> > show_help_children(bsf->priv_class, AV_OPT_FLAG_BSF_PARAM);
> > }
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