[FFmpeg-devel] [PATCH v4] Option to prevent probing for HTTP seekability

Duncan Salerno duncan.salerno at gmail.com
Tue Oct 2 23:22:44 CEST 2012


Some HLS servers return 403 when the Range header is present. Add an tri-state (seek, non seek, automatic detection) option to HTTP to control seekability (default: automatic), set to disabled by HLS to prevent the Range header being sent to probe.
---
 libavformat/hls.c  |   35 ++++++++++++++++++++++++-----------
 libavformat/http.c |   20 ++++++++++++++------
 2 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/libavformat/hls.c b/libavformat/hls.c
index 00c3cf0..1f5309b 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -212,9 +212,14 @@ static int parse_playlist(HLSContext *c, const char *url,
     int close_in = 0;
 
     if (!in) {
+        AVDictionary *opts = NULL;
         close_in = 1;
-        if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
-                              c->interrupt_callback, NULL)) < 0)
+        /* Some HLS servers dont like being sent the range header */
+        av_dict_set(&opts, "seekable", "0", 0);
+        ret = avio_open2(&in, url, AVIO_FLAG_READ,
+                         c->interrupt_callback, &opts);
+        av_dict_free(&opts);
+        if (ret < 0)
             return ret;
     }
 
@@ -325,17 +330,20 @@ fail:
 
 static int open_input(struct variant *var)
 {
+    AVDictionary *opts = NULL;
+    int ret;
     struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no];
+    av_dict_set(&opts, "seekable", "0", 0);
     if (seg->key_type == KEY_NONE) {
-        return ffurl_open(&var->input, seg->url, AVIO_FLAG_READ,
-                          &var->parent->interrupt_callback, NULL);
+        ret = ffurl_open(&var->input, seg->url, AVIO_FLAG_READ,
+                          &var->parent->interrupt_callback, &opts);
+        goto cleanup;
     } else if (seg->key_type == KEY_AES_128) {
         char iv[33], key[33], url[MAX_URL_SIZE];
-        int ret;
         if (strcmp(seg->key, var->key_url)) {
             URLContext *uc;
             if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ,
-                           &var->parent->interrupt_callback, NULL) == 0) {
+                           &var->parent->interrupt_callback, &opts) == 0) {
                 if (ffurl_read_complete(uc, var->key, sizeof(var->key))
                     != sizeof(var->key)) {
                     av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
@@ -357,17 +365,22 @@ static int open_input(struct variant *var)
             snprintf(url, sizeof(url), "crypto:%s", seg->url);
         if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ,
                                &var->parent->interrupt_callback)) < 0)
-            return ret;
+            goto cleanup;
         av_opt_set(var->input->priv_data, "key", key, 0);
         av_opt_set(var->input->priv_data, "iv", iv, 0);
-        if ((ret = ffurl_connect(var->input, NULL)) < 0) {
+        if ((ret = ffurl_connect(var->input, &opts)) < 0) {
             ffurl_close(var->input);
             var->input = NULL;
-            return ret;
+            goto cleanup;
         }
-        return 0;
+        ret = 0;
     }
-    return AVERROR(ENOSYS);
+    else
+      ret = AVERROR(ENOSYS);
+
+cleanup:
+    av_dict_free(&opts);
+    return ret;
 }
 
 static int read_data(void *opaque, uint8_t *buf, int buf_size)
diff --git a/libavformat/http.c b/libavformat/http.c
index ede4e8b..375f0a8 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -50,6 +50,7 @@ typedef struct {
     HTTPAuthState proxy_auth_state;
     char *headers;
     int willclose;          /**< Set if the server correctly handles Connection: close and will close the connection after feeding us the content. */
+    int seekable;           /**< Control seekability, 0 = disable, 1 = enable, -1 = probe. */
     int chunked_post;
     int end_chunked_post;   /**< A flag which indicates if the end of chunked encoding has been sent. */
     int end_header;         /**< A flag which indicates we have finished to read POST reply. */
@@ -64,6 +65,7 @@ typedef struct {
 #define E AV_OPT_FLAG_ENCODING_PARAM
 #define DEC AV_OPT_FLAG_DECODING_PARAM
 static const AVOption options[] = {
+{"seekable", "Control seekability of connection", OFFSET(seekable), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, D },
 {"chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
 {"headers", "custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },
 {"user-agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC},
@@ -207,7 +209,10 @@ static int http_open(URLContext *h, const char *uri, int flags)
 {
     HTTPContext *s = h->priv_data;
 
-    h->is_streamed = 1;
+    if( s->seekable == 1 )
+        h->is_streamed = 0;
+    else
+        h->is_streamed = 1;
 
     s->filesize = -1;
     av_strlcpy(s->location, uri, sizeof(s->location));
@@ -318,9 +323,9 @@ static int process_line(URLContext *h, char *line, int line_count,
                 if ((slash = strchr(p, '/')) && strlen(slash) > 0)
                     s->filesize = strtoll(slash+1, NULL, 10);
             }
-            if (!s->is_akamai || s->filesize != 2147483647)
+            if (s->seekable == -1 && (!s->is_akamai || s->filesize != 2147483647))
                 h->is_streamed = 0; /* we _can_ in fact seek */
-        } else if (!av_strcasecmp(tag, "Accept-Ranges") && !strncmp(p, "bytes", 5)) {
+        } else if (!av_strcasecmp(tag, "Accept-Ranges") && !strncmp(p, "bytes", 5) && s->seekable == -1) {
             h->is_streamed = 0;
         } else if (!av_strcasecmp (tag, "Transfer-Encoding") && !av_strncasecmp(p, "chunked", 7)) {
             s->filesize = -1;
@@ -411,10 +416,10 @@ static int http_connect(URLContext *h, const char *path, const char *local_path,
     if (!has_header(s->headers, "\r\nAccept: "))
         len += av_strlcpy(headers + len, "Accept: */*\r\n",
                           sizeof(headers) - len);
-    // Note: we send this on purpose even when s->off is 0,
+    // Note: we send this on purpose even when s->off is 0 when we're probing,
     // since it allows us to detect more reliably if a (non-conforming)
     // server supports seeking by analysing the reply headers.
-    if (!has_header(s->headers, "\r\nRange: ") && !post)
+    if (!has_header(s->headers, "\r\nRange: ") && !post && (s->off > 0 || s->seekable == -1))
         len += av_strlcatf(headers + len, sizeof(headers) - len,
                            "Range: bytes=%"PRId64"-\r\n", s->off);
 
@@ -702,7 +707,10 @@ static int http_proxy_open(URLContext *h, const char *uri, int flags)
     char *authstr;
     int new_loc;
 
-    h->is_streamed = 1;
+    if( s->seekable == 1 )
+        h->is_streamed = 0;
+    else
+        h->is_streamed = 1;
 
     av_url_split(NULL, 0, auth, sizeof(auth), hostname, sizeof(hostname), &port,
                  pathbuf, sizeof(pathbuf), uri);
-- 
1.7.9.5



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