ad_pcm: don't rely on demux packets staying valid

Change ad_pcm to copy input packet data into an internal buffer
instead of relying on the packet still existing at the next decode()
call. The extra memcpy could be avoided by improving the demuxer API a
bit but I don't feel like implementing that now. Also add a
ADCTRL_RESYNC_STREAM handler to drop buffered data from previous
stream position.

1 files changed, 23 insertions, 9 deletions

diff --git a/libmpcodecs/ad_pcm.c b/libmpcodecs/ad_pcm.c
index 6df408abd3..060d95d437 100644
--- a/libmpcodecs/ad_pcm.c
+++ b/libmpcodecs/ad_pcm.c
@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <stdbool.h>
 
 #include "talloc.h"
 #include "config.h"
@@ -35,8 +36,10 @@ static const ad_info_t info = {
 };
 
 struct ad_pcm_context {
-    unsigned char *packet_ptr;
-    int packet_len;
+    unsigned char *buffer;
+    int buffer_pos;
+    int buffer_len;
+    int buffer_size;
 };
 
 LIBAD_EXTERN(pcm)
@@ -137,8 +140,12 @@ static void uninit(sh_audio_t * sh)
 
 static int control(sh_audio_t * sh, int cmd, void *arg, ...)
 {
+    struct ad_pcm_context *ctx = sh->context;
     int skip;
     switch (cmd) {
+    case ADCTRL_RESYNC_STREAM:
+        ctx->buffer_len = 0;
+        return true;
     case ADCTRL_SKIP_FRAME:
         skip = sh->i_bps / 16;
         skip = skip & (~3);
@@ -161,23 +168,30 @@ static int decode_audio(sh_audio_t * sh_audio, unsigned char *buf, int minlen,
     len = 0;
     struct ad_pcm_context *ctx = sh_audio->context;
     while (len < minlen) {
-        if (ctx->packet_len == 0) {
+        if (ctx->buffer_len - ctx->buffer_pos <= 0) {
             double pts;
-            int plen = ds_get_packet_pts(sh_audio->ds, &ctx->packet_ptr, &pts);
+            unsigned char *ptr;
+            int plen = ds_get_packet_pts(sh_audio->ds, &ptr, &pts);
             if (plen < 0)
                 break;
-            ctx->packet_len = plen;
+            if (ctx->buffer_size < plen) {
+                talloc_free(ctx->buffer);
+                ctx->buffer = talloc_size(ctx, plen);
+                ctx->buffer_size = plen;
+            }
+            memcpy(ctx->buffer, ptr, plen);
+            ctx->buffer_len = plen;
+            ctx->buffer_pos = 0;
             if (pts != MP_NOPTS_VALUE) {
                 sh_audio->pts = pts;
                 sh_audio->pts_bytes = 0;
             }
         }
-        int from_stored = ctx->packet_len;
+        int from_stored = ctx->buffer_len - ctx->buffer_pos;
         if (from_stored > minlen - len)
             from_stored = minlen - len;
-        memcpy(buf + len, ctx->packet_ptr, from_stored);
-        ctx->packet_len -= from_stored;
-        ctx->packet_ptr += from_stored;
+        memcpy(buf + len, ctx->buffer + ctx->buffer_pos, from_stored);
+        ctx->buffer_pos += from_stored;
         sh_audio->pts_bytes += from_stored;
         len += from_stored;
     }