[FFmpeg-devel] [PATCH 08/11] fftools/opt_common: switch to avcodec_get_supported_config()
Niklas Haas
ffmpeg at haasn.xyz
Mon Apr 8 14:15:35 EEST 2024
On Sat, 06 Apr 2024 21:10:45 -0300 James Almer <jamrial at gmail.com> wrote:
> On 4/6/2024 8:38 AM, Niklas Haas wrote:
> > 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);
>
> I don't think this is needed if it's called immediately after
> av_bprint_init().
get_channel_layout_desc() is called in a loop.
>
> > + 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);
>
> Yeah, this is good. Thanks.
>
> >
> > 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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> >> ffmpeg-devel at ffmpeg.org
> >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >>
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> >
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