af_lavcac3enc: make the filter work without FFmpeg internals

The only FFmpeg internal symbols required were some constants. Define
them in the file itself instead. Also add some checks and fixes to
make the code more robust and fix a potential memory corruption
problem.

1 files changed, 20 insertions, 5 deletions

diff --git a/libaf/af_lavcac3enc.c b/libaf/af_lavcac3enc.c
index 9323326d53..59eb08ac3b 100644
--- a/libaf/af_lavcac3enc.c
+++ b/libaf/af_lavcac3enc.c
@@ -24,14 +24,22 @@
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>
+#include <assert.h>
 
 #include "config.h"
 #include "af.h"
 #include "reorder_ch.h"
 
 #include "libavcodec/avcodec.h"
-#include "libavcodec/ac3.h"
-#include "libavutil/intreadwrite.h"
+#include "ffmpeg_files/intreadwrite.h"
+
+#define AC3_MAX_CHANNELS 6
+#define AC3_MAX_CODED_FRAME_SIZE 3840
+#define AC3_FRAME_SIZE (6  * 256)
+const uint16_t ac3_bitrate_tab[19] = {
+    32, 40, 48, 56, 64, 80, 96, 112, 128,
+    160, 192, 224, 256, 320, 384, 448, 512, 576, 640
+};
 
 // Data for specific instances of this filter
 typedef struct af_ac3enc_s {
@@ -39,6 +47,7 @@ typedef struct af_ac3enc_s {
     struct AVCodecContext *lavc_actx;
     int add_iec61937_header;
     int bit_rate;
+    int pending_data_size;
     char *pending_data;
     int pending_len;
     int expect_len;
@@ -63,6 +72,7 @@ static int control(struct af_instance_s *af, int cmd, void *arg)
 
         s->pending_len = 0;
         s->expect_len = AC3_FRAME_SIZE * data->nch * data->bps;
+        assert(s->expect_len <= s->pending_data_size);
         if (s->add_iec61937_header)
             af->mul = (double)AC3_FRAME_SIZE * 2 * 2 / s->expect_len;
         else
@@ -102,6 +112,11 @@ static int control(struct af_instance_s *af, int cmd, void *arg)
                 return AF_ERROR;
             }
         }
+        if (s->lavc_actx->frame_size != AC3_FRAME_SIZE) {
+            mp_msg(MSGT_AFILTER, MSGL_ERR, "lavcac3enc: unexpected ac3 "
+                   "encoder frame size %d\n", s->lavc_actx->frame_size);
+            return AF_ERROR;
+        }
         af->data->format = AF_FORMAT_AC3_BE;
         af->data->nch = 2;
         return test_output_res;
@@ -116,7 +131,7 @@ static int control(struct af_instance_s *af, int cmd, void *arg)
             s->bit_rate *= 1000;
         if (s->bit_rate) {
             for (i = 0; i < 19; ++i)
-                if (ff_ac3_bitrate_tab[i] * 1000 == s->bit_rate)
+                if (ac3_bitrate_tab[i] * 1000 == s->bit_rate)
                     break;
             if (i >= 19) {
                 mp_msg(MSGT_AFILTER, MSGL_WARN, "af_lavcac3enc unable set unsupported "
@@ -262,8 +277,8 @@ static af_data_t* play(struct af_instance_s* af, af_data_t* data)
 static int af_open(af_instance_t* af){
 
     af_ac3enc_t *s = calloc(1,sizeof(af_ac3enc_t));
-    int pending_space = 2 * AC3_MAX_CHANNELS * AC3_FRAME_SIZE;
-    s->pending_data = calloc(pending_space, sizeof(char));
+    s->pending_data_size = 2 * AF_NCH * AC3_FRAME_SIZE;
+    s->pending_data = malloc(s->pending_data_size);
 
     af->control=control;
     af->uninit=uninit;