Compile error with new ffmpeg

[stevenfalco]

I just downloaded a new copy of the ffmpeg snapshot (2025-04-27).

ffmpeg built properly, but when I tried building makemkv-oss-1.18.1 I got a few errors. I attached the build log, but here are the highlights:

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libffabi/src/ffabi.c:214:9: error: implicit declaration of function ‘avcodec_close’; did you mean ‘avcodec_license’? [-Wimplicit-function-declaration]
  214 |         avcodec_close(ctx->avctx);
      |         ^~~~~~~~~~~~~

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libffabi/src/ffabi.c:377:25: error: ‘FF_PROFILE_UNKNOWN’ undeclared (first use in this function); did you mean ‘FFM_PROFILE_UNKNOWN’?
  377 |         info->profile : FF_PROFILE_UNKNOWN;
      |                         ^~~~~~~~~~~~~~~~~~

I then went back to an older copy of ffmpeg from 2024-10-04 and I was able to build makemkv-oss-1.18.1 without any problems.

Apparently, ffmpeg has changed its API recently, and makemkv-oss-1.18.1 cannot build using the new API.

[stevenfalco]

I looked at the ffmpeg git repo, and found that avcodec_close() was deprecated, and now has been removed. Please see commit 0d48da2db in the ffmpeg source git:

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    avcodec: remove deprecated FF_API_AVCODEC_CLOSE
    
    Deprecated since 2024-02-09.
    
    Signed-off-by: James Almer <jamrial@gmail.com>

There is also this note describing the API change to avcodec_close():

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* @deprecated Do not use this function. Use avcodec_free_context() to destroy a
* codec context (either open or closed). Opening and closing a codec context
* multiple times is not supported anymore -- use multiple codec contexts
* instead.

Regarding FF_PROFILE_UNKNOWN, I found commit 822432769 which removes it:

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    avcodec: remove deprecated FF_API_FF_PROFILE_LEVEL
    
    Deprecated since 2023-09-06.
    
    Signed-off-by: James Almer <jamrial@gmail.com>

And there is this note:

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/** @deprecated The following define is deprecated; use AV_LEVEL_UNKOWN
 * in defs.h instead. */

[elfurbe]

These were good hints. The following patch should make ffabi.c from makemkv-oss-1.18.1 compile against libavcodec.so.62, if anyone else is trying to work that out. Fair warning, no idea if this breaks compat with earlier versions of libavcodec. Also worth saying I do not generate patches with any frequency, so if this doesn't apply properly the changes are easy to make by hand.

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--- ffabi.c 2025-04-05 10:13:02.000000000 -0700
+++ ffabi.c 2025-05-11 01:32:20.691298362 -0700
@@ -211,8 +211,7 @@
     av_packet_free(&ctx->pck);

     if (ctx->avctx) {
-        avcodec_close(ctx->avctx);
-        av_free(ctx->avctx);
+        avcodec_free_context(ctx->avctx);
     }

     av_free(ctx);
@@ -374,7 +373,7 @@
 #endif

     ctx->avctx->profile = (info->profile != FFM_PROFILE_UNKNOWN) ?
-        info->profile : FF_PROFILE_UNKNOWN;
+        info->profile : AV_PROFILE_UNKNOWN;

     if ((CodecFlags&FFM_CODEC_FLAG_GLOBAL_HEADER)!=0)
         ctx->avctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
@@ -420,8 +419,7 @@
     av_freep(&ctx->frame_extended_data);

     if (ctx->avctx) {
-        avcodec_close(ctx->avctx);
-        av_free(ctx->avctx);
+        avcodec_free_context(ctx->avctx);
     }

     av_free(ctx);
@@ -604,7 +602,7 @@
     info->capabilities = codec->capabilities;
     if (codec->profiles) {
         for (i=0;i<32;i++) {
-            if (codec->profiles[i].profile==FF_PROFILE_UNKNOWN)
+            if (codec->profiles[i].profile==AV_PROFILE_UNKNOWN)
                 break;
             info->profiles_names[i]=codec->profiles[i].name;
             info->profiles_values[i]=codec->profiles[i].profile;
@@ -695,8 +693,7 @@
     }

     if (avctx) {
-        avcodec_close(avctx);
-        av_free(avctx);
+        avcodec_free_context(avctx);
     }
     return err;
 }

[innerlib]

I was experiencing libc/pthread segfaults originating in ffm_mlp_read_syncframe which is part of the patch. It compiles cleanly, but looking harder at avcodec_free_context, it takes a pointer to a pointer. Amending the patch to...

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--- ffabi.c 2025-04-05 10:13:02.000000000 -0700
+++ ffabi.c 2025-05-11 01:32:20.691298362 -0700
@@ -211,8 +211,7 @@
     av_packet_free(&ctx->pck);

     if (ctx->avctx) {
-        avcodec_close(ctx->avctx);
-        av_free(ctx->avctx);
+        avcodec_free_context(&(ctx->avctx));
     }

     av_free(ctx);
@@ -374,7 +373,7 @@
 #endif

     ctx->avctx->profile = (info->profile != FFM_PROFILE_UNKNOWN) ?
-        info->profile : FF_PROFILE_UNKNOWN;
+        info->profile : AV_PROFILE_UNKNOWN;

     if ((CodecFlags&FFM_CODEC_FLAG_GLOBAL_HEADER)!=0)
         ctx->avctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
@@ -420,8 +419,7 @@
     av_freep(&ctx->frame_extended_data);

     if (ctx->avctx) {
-        avcodec_close(ctx->avctx);
-        av_free(ctx->avctx);
+        avcodec_free_context(&(ctx->avctx));
     }

     av_free(ctx);
@@ -604,7 +602,7 @@
     info->capabilities = codec->capabilities;
     if (codec->profiles) {
         for (i=0;i<32;i++) {
-            if (codec->profiles[i].profile==FF_PROFILE_UNKNOWN)
+            if (codec->profiles[i].profile==AV_PROFILE_UNKNOWN)
                 break;
             info->profiles_names[i]=codec->profiles[i].name;
             info->profiles_values[i]=codec->profiles[i].profile;
@@ -695,8 +693,7 @@
     }

     if (avctx) {
-        avcodec_close(avctx);
-        av_free(avctx);
+        avcodec_free_context(&avctx);
     }
     return err;
 }

Hasn't segfault'd yet.