cmdutils: extend -h to allow printing codec details.

1 files changed, 119 insertions, 1 deletions

diff --git a/cmdutils.c b/cmdutils.c
index bc5cb8aae2..55cf3f082a 100644
--- a/cmdutils.c
+++ b/cmdutils.c
@@ -132,7 +132,7 @@ void show_help_options(const OptionDef *options, const char *msg, int req_flags,
             first = 0;
         }
         av_strlcpy(buf, po->name, sizeof(buf));
-        if (po->flags & HAS_ARG) {
+        if (po->argname) {
             av_strlcat(buf, " ", sizeof(buf));
             av_strlcat(buf, po->argname, sizeof(buf));
         }
@@ -642,6 +642,65 @@ int show_formats(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 = c->field;                                            \
+                                                                             \
+        printf("    Supported " list_name ":");                              \
+        while (*p != term) {                                                 \
+            get_name(*p);                                                    \
+            printf(" %s", name);                                             \
+            p++;                                                             \
+        }                                                                    \
+        printf("\n");                                                        \
+    }                                                                        \
+
+static void print_codec(const AVCodec *c)
+{
+    int encoder = av_codec_is_encoder(c);
+
+    printf("%s %s [%s]:\n", encoder ? "Encoder" : "Decoder", c->name,
+           c->long_name ? c->long_name : "");
+
+    if (c->type == AVMEDIA_TYPE_VIDEO) {
+        printf("    Threading capabilities: ");
+        switch (c->capabilities & (CODEC_CAP_FRAME_THREADS |
+                                   CODEC_CAP_SLICE_THREADS)) {
+        case CODEC_CAP_FRAME_THREADS |
+             CODEC_CAP_SLICE_THREADS: printf("frame and slice"); break;
+        case CODEC_CAP_FRAME_THREADS: printf("frame");           break;
+        case CODEC_CAP_SLICE_THREADS: printf("slice");           break;
+        default:                      printf("no");              break;
+        }
+        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 PixelFormat, "pixel formats",
+                          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);
+    PRINT_CODEC_SUPPORTED(c, channel_layouts, uint64_t, "channel layouts",
+                          0, GET_CH_LAYOUT_DESC);
+
+    if (c->priv_class) {
+        show_help_children(c->priv_class,
+                           AV_OPT_FLAG_ENCODING_PARAM |
+                           AV_OPT_FLAG_DECODING_PARAM);
+    }
+}
+
 static char get_media_type_char(enum AVMediaType type)
 {
     switch (type) {
@@ -842,6 +901,65 @@ int show_sample_fmts(const char *opt, const char *arg)
     return 0;
 }
 
+static void show_help_codec(const char *name, int encoder)
+{
+    const AVCodecDescriptor *desc;
+    const AVCodec *codec;
+
+    if (!name) {
+        av_log(NULL, AV_LOG_ERROR, "No codec name specified.\n");
+        return;
+    }
+
+    codec = encoder ? avcodec_find_encoder_by_name(name) :
+                      avcodec_find_decoder_by_name(name);
+
+    if (codec)
+        print_codec(codec);
+    else if ((desc = avcodec_descriptor_get_by_name(name))) {
+        int printed = 0;
+
+        while ((codec = next_codec_for_id(desc->id, codec, encoder))) {
+            printed = 1;
+            print_codec(codec);
+        }
+
+        if (!printed) {
+            av_log(NULL, AV_LOG_ERROR, "Codec '%s' is known to Libav, "
+                   "but no %s for it are available. Libav might need to be "
+                   "recompiled with additional external libraries.\n",
+                   name, encoder ? "encoders" : "decoders");
+        }
+    } else {
+        av_log(NULL, AV_LOG_ERROR, "Codec '%s' is not recognized by Libav.\n",
+               name);
+    }
+}
+
+int show_help(const char *opt, const char *arg)
+{
+    char *topic, *par;
+    av_log_set_callback(log_callback_help);
+
+    topic = av_strdup(arg ? arg : "");
+    par = strchr(topic, '=');
+    if (par)
+        *par++ = 0;
+
+    if (!*topic) {
+        show_help_default(topic, par);
+    } else if (!strcmp(topic, "decoder")) {
+        show_help_codec(par, 0);
+    } else if (!strcmp(topic, "encoder")) {
+        show_help_codec(par, 1);
+    } else {
+        show_help_default(topic, par);
+    }
+
+    av_freep(&topic);
+    return 0;
+}
+
 int read_yesno(void)
 {
     int c = getchar();