lavc: Drop exporting 2-pass encoding stats

These variables are coming from mpegvideoenc where are supposedly used
as bit counters on various frame properties. However their use is
unclear as they lack documentation, are available only from a very small
subset of encoders, and they are hardly used in the wild. Also frame_bits
in aacenc is employed in a similar way.

Remove this functionality from AVCodecContex, these variable are mostly
frame properties, and too few encoders support setting them with anything
useful.
Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

libavcodec/aacenc.c

@@ -510,6 +510,7 @@ static int aac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
     ChannelElement *cpe;
     int i, ch, w, g, chans, tag, start_ch, ret;
     int chan_el_counter[4];
+    int frame_bits;
     FFPsyWindowInfo windows[AAC_MAX_CHANNELS];
 
     if (s->last_frame == 2)
@@ -577,8 +578,6 @@ static int aac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
     }
 
     do {
-        int frame_bits;
-
         init_put_bits(&s->pb, avpkt->data, avpkt->size);
 
         if ((avctx->frame_number & 0xFF)==1 && !(avctx->flags & AV_CODEC_FLAG_BITEXACT))
@@ -651,11 +650,16 @@ static int aac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
 
     put_bits(&s->pb, 3, TYPE_END);
     flush_put_bits(&s->pb);
-    avctx->frame_bits = put_bits_count(&s->pb);
+    frame_bits = put_bits_count(&s->pb);
+#if FF_API_STAT_BITS
+FF_DISABLE_DEPRECATION_WARNINGS
+    avctx->frame_bits = frame_bits;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
     // rate control stuff
     if (!(avctx->flags & AV_CODEC_FLAG_QSCALE)) {
-        float ratio = avctx->bit_rate * 1024.0f / avctx->sample_rate / avctx->frame_bits;
+        float ratio = avctx->bit_rate * 1024.0f / avctx->sample_rate / frame_bits;
         s->lambda *= ratio;
         s->lambda = FFMIN(s->lambda, 65536.f);
     }

libavcodec/avcodec.h

@@ -2437,22 +2437,29 @@ typedef struct AVCodecContext {
                             /* This doesn't take account of any particular  */
                             /* headers inside the transmitted RTP payload.  */
 
+#if FF_API_STAT_BITS
     /* statistics, used for 2-pass encoding */
+    attribute_deprecated
     int mv_bits;
+    attribute_deprecated
     int header_bits;
+    attribute_deprecated
     int i_tex_bits;
+    attribute_deprecated
     int p_tex_bits;
+    attribute_deprecated
     int i_count;
+    attribute_deprecated
     int p_count;
+    attribute_deprecated
     int skip_count;
+    attribute_deprecated
     int misc_bits;
 
-    /**
-     * number of bits used for the previously encoded frame
-     * - encoding: Set by libavcodec.
-     * - decoding: unused
-     */
+    /** @deprecated this field is unused */
+    attribute_deprecated
     int frame_bits;
+#endif
 
     /**
      * pass1 encoding statistics output buffer

libavcodec/mpegvideo_enc.c

@@ -1659,6 +1659,8 @@ vbv_retry:
         if (encode_picture(s, s->picture_number) < 0)
             return -1;
 
+#if FF_API_STAT_BITS
+FF_DISABLE_DEPRECATION_WARNINGS
         avctx->header_bits = s->header_bits;
         avctx->mv_bits     = s->mv_bits;
         avctx->misc_bits   = s->misc_bits;
@@ -1668,6 +1670,8 @@ vbv_retry:
         // FIXME f/b_count in avctx
         avctx->p_count     = s->mb_num - s->i_count - s->skip_count;
         avctx->skip_count  = s->skip_count;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
         frame_end(s);
 
@@ -1727,9 +1731,9 @@ vbv_retry:
         }
 
         if (s->avctx->flags & AV_CODEC_FLAG_PASS1)
-            assert(avctx->header_bits + avctx->mv_bits + avctx->misc_bits +
-                   avctx->i_tex_bits + avctx->p_tex_bits ==
-                       put_bits_count(&s->pb));
+            assert(put_bits_count(&s->pb) == s->header_bits + s->mv_bits +
+                                             s->misc_bits + s->i_tex_bits +
+                                             s->p_tex_bits);
         flush_put_bits(&s->pb);
         s->frame_bits  = put_bits_count(&s->pb);
 
@@ -1811,7 +1815,12 @@ FF_ENABLE_DEPRECATION_WARNINGS
 #endif
         }
         s->total_bits     += s->frame_bits;
+#if FF_API_STAT_BITS
+FF_DISABLE_DEPRECATION_WARNINGS
         avctx->frame_bits  = s->frame_bits;
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
+
 
         pkt->pts = s->current_picture.f->pts;
         if (!s->low_delay && s->pict_type != AV_PICTURE_TYPE_B) {

libavcodec/options_table.h

@@ -121,6 +121,7 @@ static const AVOption avcodec_options[] = {
 #endif
 {"b_strategy", "strategy to choose between I/P/B-frames", OFFSET(b_frame_strategy), AV_OPT_TYPE_INT, {.i64 = 0 }, INT_MIN, INT_MAX, V|E},
 {"ps", "RTP payload size in bytes", OFFSET(rtp_payload_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX, V|E},
+#if FF_API_STAT_BITS
 {"mv_bits", NULL, OFFSET(mv_bits), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
 {"header_bits", NULL, OFFSET(header_bits), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
 {"i_tex_bits", NULL, OFFSET(i_tex_bits), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
@@ -130,6 +131,7 @@ static const AVOption avcodec_options[] = {
 {"skip_count", NULL, OFFSET(skip_count), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
 {"misc_bits", NULL, OFFSET(misc_bits), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
 {"frame_bits", NULL, OFFSET(frame_bits), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
+#endif
 {"codec_tag", NULL, OFFSET(codec_tag), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, INT_MIN, INT_MAX},
 {"bug", "work around not autodetected encoder bugs", OFFSET(workaround_bugs), AV_OPT_TYPE_FLAGS, {.i64 = FF_BUG_AUTODETECT }, INT_MIN, INT_MAX, V|D, "bug"},
 {"autodetect", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_BUG_AUTODETECT }, INT_MIN, INT_MAX, V|D, "bug"},

libavcodec/version.h

@@ -186,5 +186,8 @@
 #ifndef FF_API_CODER_TYPE
 #define FF_API_CODER_TYPE        (LIBAVCODEC_VERSION_MAJOR < 59)
 #endif
+#ifndef FF_API_STAT_BITS
+#define FF_API_STAT_BITS         (LIBAVCODEC_VERSION_MAJOR < 59)
+#endif
 
 #endif /* AVCODEC_VERSION_H */