avcodec: parse options from AVCodec.bsfs

Fixes a bug that would prevent using multiple comma-separated filters,
and allows options to be passed to each filter.

Based on similar loop in ffmpeg_opt.c's new_output_stream().
Signed-off-by: Aman Gupta <aman@tmm1.net>

libavcodec/decode.c

@@ -36,6 +36,7 @@
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
 #include "libavutil/intmath.h"
+#include "libavutil/opt.h"
 
 #include "avcodec.h"
 #include "bytestream.h"
@@ -195,27 +196,33 @@ static int bsfs_init(AVCodecContext *avctx)
     while (bsfs_str && *bsfs_str) {
         AVBSFContext **tmp;
         const AVBitStreamFilter *filter;
-        char *bsf;
+        char *bsf, *bsf_options_str, *bsf_name;
 
         bsf = av_get_token(&bsfs_str, ",");
         if (!bsf) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
+        bsf_name = av_strtok(bsf, "=", &bsf_options_str);
+        if (!bsf_name) {
+            av_freep(&bsf);
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
 
-        filter = av_bsf_get_by_name(bsf);
+        filter = av_bsf_get_by_name(bsf_name);
         if (!filter) {
             av_log(avctx, AV_LOG_ERROR, "A non-existing bitstream filter %s "
                    "requested by a decoder. This is a bug, please report it.\n",
-                   bsf);
-            ret = AVERROR_BUG;
+                   bsf_name);
             av_freep(&bsf);
+            ret = AVERROR_BUG;
             goto fail;
         }
-        av_freep(&bsf);
 
         tmp = av_realloc_array(s->bsfs, s->nb_bsfs + 1, sizeof(*s->bsfs));
         if (!tmp) {
+            av_freep(&bsf);
             ret = AVERROR(ENOMEM);
             goto fail;
         }
@@ -223,8 +230,10 @@ static int bsfs_init(AVCodecContext *avctx)
         s->nb_bsfs++;
 
         ret = av_bsf_alloc(filter, &s->bsfs[s->nb_bsfs - 1]);
-        if (ret < 0)
+        if (ret < 0) {
+            av_freep(&bsf);
             goto fail;
+        }
 
         if (s->nb_bsfs == 1) {
             /* We do not currently have an API for passing the input timebase into decoders,
@@ -238,12 +247,38 @@ static int bsfs_init(AVCodecContext *avctx)
             ret = avcodec_parameters_copy(s->bsfs[s->nb_bsfs - 1]->par_in,
                                           s->bsfs[s->nb_bsfs - 2]->par_out);
         }
-        if (ret < 0)
+        if (ret < 0) {
+            av_freep(&bsf);
             goto fail;
+        }
+
+        if (bsf_options_str && filter->priv_class) {
+            const AVOption *opt = av_opt_next(s->bsfs[s->nb_bsfs - 1]->priv_data, NULL);
+            const char * shorthand[2] = {NULL};
+
+            if (opt)
+                shorthand[0] = opt->name;
+
+            ret = av_opt_set_from_string(s->bsfs[s->nb_bsfs - 1]->priv_data, bsf_options_str, shorthand, "=", ":");
+            if (ret < 0) {
+                if (ret != AVERROR(ENOMEM)) {
+                    av_log(avctx, AV_LOG_ERROR, "Invalid options for bitstream filter %s "
+                           "requested by the decoder. This is a bug, please report it.\n",
+                           bsf_name);
+                    ret = AVERROR_BUG;
+                }
+                av_freep(&bsf);
+                goto fail;
+            }
+        }
+        av_freep(&bsf);
 
         ret = av_bsf_init(s->bsfs[s->nb_bsfs - 1]);
         if (ret < 0)
             goto fail;
+
+        if (*bsfs_str)
+            bsfs_str++;
     }
 
     return 0;