[FFmpeg-devel] [PATCH 08/11] fftools/opt_common: switch to avcodec_get_supported_config()
James Almer
jamrial at gmail.com
Sun Apr 7 03:10:45 EEST 2024
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().
> + 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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>>
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