From: Jan Engelhardt <jengelh@inai.de>
Date: 2016-04-10 23:23:53.138440254 +0200

Improve the error messages a bit to say what's really going on
(in light of a reduced build).

---
 fftools/ffmpeg.c        |    2 +-
 fftools/ffmpeg_filter.c |    4 ++--
 fftools/ffmpeg_opt.c    |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

Index: ffmpeg-5.0/fftools/ffmpeg.c
===================================================================
--- ffmpeg-5.0.orig/fftools/ffmpeg.c	2022-01-14 19:45:39.000000000 +0100
+++ ffmpeg-5.0/fftools/ffmpeg.c	2022-02-04 08:16:14.606621540 +0100
@@ -2871,7 +2871,7 @@ static int init_input_stream(int ist_ind
     if (ist->decoding_needed) {
         const AVCodec *codec = ist->dec;
         if (!codec) {
-            snprintf(error, error_len, "Decoder (codec %s) not found for input stream #%d:%d",
+            snprintf(error, error_len, "This build of ffmpeg does not include a \"%s\" decoder needed for input stream #%d:%d.",
                     avcodec_get_name(ist->dec_ctx->codec_id), ist->file_index, ist->st->index);
             return AVERROR(EINVAL);
         }
Index: ffmpeg-5.0/fftools/ffmpeg_filter.c
===================================================================
--- ffmpeg-5.0.orig/fftools/ffmpeg_filter.c	2022-01-14 19:45:39.000000000 +0100
+++ ffmpeg-5.0/fftools/ffmpeg_filter.c	2022-02-04 08:16:14.607621538 +0100
@@ -925,7 +925,7 @@ static int configure_input_filter(Filter
 {
     if (!ifilter->ist->dec) {
         av_log(NULL, AV_LOG_ERROR,
-               "No decoder for stream #%d:%d, filtering impossible\n",
+               "This build of ffmpeg does not have a suitable decoder for stream #%d:%d enabled, filtering impossible\n",
                ifilter->ist->file_index, ifilter->ist->st->index);
         return AVERROR_DECODER_NOT_FOUND;
     }
@@ -1094,7 +1094,7 @@ int configure_filtergraph(FilterGraph *f
         if (!ost->enc) {
             /* identical to the same check in ffmpeg.c, needed because
                complex filter graphs are initialized earlier */
-            av_log(NULL, AV_LOG_ERROR, "Encoder (codec %s) not found for output stream #%d:%d\n",
+            av_log(NULL, AV_LOG_ERROR, "This build of ffmpeg does not include a \"%s\" encoder needed for output stream #%d:%d.\n",
                      avcodec_get_name(ost->st->codecpar->codec_id), ost->file_index, ost->index);
             ret = AVERROR(EINVAL);
             goto fail;
Index: ffmpeg-5.0/fftools/ffmpeg_opt.c
===================================================================
--- ffmpeg-5.0.orig/fftools/ffmpeg_opt.c	2022-01-14 19:45:39.000000000 +0100
+++ ffmpeg-5.0/fftools/ffmpeg_opt.c	2022-02-04 08:16:14.607621538 +0100
@@ -1406,7 +1406,7 @@ static int choose_encoder(OptionsContext
             if (!ost->enc) {
                 av_log(NULL, AV_LOG_FATAL, "Automatic encoder selection failed for "
                        "output stream #%d:%d. Default encoder for format %s (codec %s) is "
-                       "probably disabled. Please choose an encoder manually.\n",
+                       "probably disabled or this build of ffmpeg does not include that codec. Please choose an encoder manually.\n",
                        ost->file_index, ost->index, s->oformat->name,
                        avcodec_get_name(ost->st->codecpar->codec_id));
                 return AVERROR_ENCODER_NOT_FOUND;