[FFmpeg-devel] [PATCH] ffmpeg: remove misleading and incorrect error messages

wm4 nfxjfg at googlemail.com
Thu Jun 15 19:59:59 EEST 2017


It is wrong/incorrect in two aspects:
1. The pixel format is not enough to guarantee that the resulting file
   will be any more compatible with media players.
2. Media players not supporting higher profiles are not necessarily
   outdated (in fact this is simply an arrogant statement that
   libavcodec can handle these particular features).

You could add that there are plenty of other ways to produce widely
incompatible files with ffmpeg, and these don't show any warnings.

What we really want to do here is defaulting to codec profiles that
have wide compatibility, such as baseline/main/high for h264. Also,
if an encoder does not accept certain pixfmts, we should automatically
convert them to a pixfmt the encoder can accept. But the existin
message certainly is not appropriate.

It also works for 2 specific encoders only. We should remove the
message for the reason alone to avoid that this code grows in the
future, and becomes a maintenance burden.
---
 ffmpeg.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/ffmpeg.c b/ffmpeg.c
index 6170bd453c..a783e6e04b 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -3343,20 +3343,7 @@ static int init_output_stream_encode(OutputStream *ost)
             ost->frame_aspect_ratio.num ? // overridden by the -aspect cli option
             av_mul_q(ost->frame_aspect_ratio, (AVRational){ enc_ctx->height, enc_ctx->width }) :
             av_buffersink_get_sample_aspect_ratio(ost->filter->filter);
-        if (!strncmp(ost->enc->name, "libx264", 7) &&
-            enc_ctx->pix_fmt == AV_PIX_FMT_NONE &&
-            av_buffersink_get_format(ost->filter->filter) != AV_PIX_FMT_YUV420P)
-            av_log(NULL, AV_LOG_WARNING,
-                   "No pixel format specified, %s for H.264 encoding chosen.\n"
-                   "Use -pix_fmt yuv420p for compatibility with outdated media players.\n",
-                   av_get_pix_fmt_name(av_buffersink_get_format(ost->filter->filter)));
-        if (!strncmp(ost->enc->name, "mpeg2video", 10) &&
-            enc_ctx->pix_fmt == AV_PIX_FMT_NONE &&
-            av_buffersink_get_format(ost->filter->filter) != AV_PIX_FMT_YUV420P)
-            av_log(NULL, AV_LOG_WARNING,
-                   "No pixel format specified, %s for MPEG-2 encoding chosen.\n"
-                   "Use -pix_fmt yuv420p for compatibility with outdated media players.\n",
-                   av_get_pix_fmt_name(av_buffersink_get_format(ost->filter->filter)));
+
         enc_ctx->pix_fmt = av_buffersink_get_format(ost->filter->filter);
         if (dec_ctx)
             enc_ctx->bits_per_raw_sample = FFMIN(dec_ctx->bits_per_raw_sample,
-- 
2.11.0



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