libavformat: Rename the applehttp protocol to hls

Keep the old protocol name around for backwards compatibility
until the next bump.

Deprecate the method of implicitly assuming the nested protocol.
For applehttp://server/path, it might have felt logical, but
supporting hls://server/path isn't quite as intuitive. Therefore
only support hls+http://server/path from now on.

Using this protocol at all is discouraged, since the hls demuxer
is more complete and fits into the architecture better. There
have been cases where the protocol implementation worked better
than the demuxer, but this should no longer be the case.

Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 341 insertions, 0 deletions

diff --git a/libavformat/hlsproto.c b/libavformat/hlsproto.c
new file mode 100644
index 0000000000..244f270398
--- /dev/null
+++ b/libavformat/hlsproto.c
@@ -0,0 +1,341 @@
+/*
+ * Apple HTTP Live Streaming Protocol Handler
+ * Copyright (c) 2010 Martin Storsjo
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Apple HTTP Live Streaming Protocol Handler
+ * http://tools.ietf.org/html/draft-pantos-http-live-streaming
+ */
+
+#include "libavutil/avstring.h"
+#include "avformat.h"
+#include "internal.h"
+#include "url.h"
+#include "version.h"
+#include <unistd.h>
+
+/*
+ * An apple http stream consists of a playlist with media segment files,
+ * played sequentially. There may be several playlists with the same
+ * video content, in different bandwidth variants, that are played in
+ * parallel (preferrably only one bandwidth variant at a time). In this case,
+ * the user supplied the url to a main playlist that only lists the variant
+ * playlists.
+ *
+ * If the main playlist doesn't point at any variants, we still create
+ * one anonymous toplevel variant for this, to maintain the structure.
+ */
+
+struct segment {
+    int duration;
+    char url[MAX_URL_SIZE];
+};
+
+struct variant {
+    int bandwidth;
+    char url[MAX_URL_SIZE];
+};
+
+typedef struct AppleHTTPContext {
+    char playlisturl[MAX_URL_SIZE];
+    int target_duration;
+    int start_seq_no;
+    int finished;
+    int n_segments;
+    struct segment **segments;
+    int n_variants;
+    struct variant **variants;
+    int cur_seq_no;
+    URLContext *seg_hd;
+    int64_t last_load_time;
+} AppleHTTPContext;
+
+static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
+{
+    int len = ff_get_line(s, buf, maxlen);
+    while (len > 0 && isspace(buf[len - 1]))
+        buf[--len] = '\0';
+    return len;
+}
+
+static void free_segment_list(AppleHTTPContext *s)
+{
+    int i;
+    for (i = 0; i < s->n_segments; i++)
+        av_free(s->segments[i]);
+    av_freep(&s->segments);
+    s->n_segments = 0;
+}
+
+static void free_variant_list(AppleHTTPContext *s)
+{
+    int i;
+    for (i = 0; i < s->n_variants; i++)
+        av_free(s->variants[i]);
+    av_freep(&s->variants);
+    s->n_variants = 0;
+}
+
+struct variant_info {
+    char bandwidth[20];
+};
+
+static void handle_variant_args(struct variant_info *info, const char *key,
+                                int key_len, char **dest, int *dest_len)
+{
+    if (!strncmp(key, "BANDWIDTH=", key_len)) {
+        *dest     =        info->bandwidth;
+        *dest_len = sizeof(info->bandwidth);
+    }
+}
+
+static int parse_playlist(URLContext *h, const char *url)
+{
+    AppleHTTPContext *s = h->priv_data;
+    AVIOContext *in;
+    int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
+    char line[1024];
+    const char *ptr;
+
+    if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
+                          &h->interrupt_callback, NULL)) < 0)
+        return ret;
+
+    read_chomp_line(in, line, sizeof(line));
+    if (strcmp(line, "#EXTM3U"))
+        return AVERROR_INVALIDDATA;
+
+    free_segment_list(s);
+    s->finished = 0;
+    while (!in->eof_reached) {
+        read_chomp_line(in, line, sizeof(line));
+        if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
+            struct variant_info info = {{0}};
+            is_variant = 1;
+            ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
+                               &info);
+            bandwidth = atoi(info.bandwidth);
+        } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
+            s->target_duration = atoi(ptr);
+        } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
+            s->start_seq_no = atoi(ptr);
+        } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
+            s->finished = 1;
+        } else if (av_strstart(line, "#EXTINF:", &ptr)) {
+            is_segment = 1;
+            duration = atoi(ptr);
+        } else if (av_strstart(line, "#", NULL)) {
+            continue;
+        } else if (line[0]) {
+            if (is_segment) {
+                struct segment *seg = av_malloc(sizeof(struct segment));
+                if (!seg) {
+                    ret = AVERROR(ENOMEM);
+                    goto fail;
+                }
+                seg->duration = duration;
+                ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
+                dynarray_add(&s->segments, &s->n_segments, seg);
+                is_segment = 0;
+            } else if (is_variant) {
+                struct variant *var = av_malloc(sizeof(struct variant));
+                if (!var) {
+                    ret = AVERROR(ENOMEM);
+                    goto fail;
+                }
+                var->bandwidth = bandwidth;
+                ff_make_absolute_url(var->url, sizeof(var->url), url, line);
+                dynarray_add(&s->variants, &s->n_variants, var);
+                is_variant = 0;
+            }
+        }
+    }
+    s->last_load_time = av_gettime();
+
+fail:
+    avio_close(in);
+    return ret;
+}
+
+static int applehttp_close(URLContext *h)
+{
+    AppleHTTPContext *s = h->priv_data;
+
+    free_segment_list(s);
+    free_variant_list(s);
+    ffurl_close(s->seg_hd);
+    return 0;
+}
+
+static int applehttp_open(URLContext *h, const char *uri, int flags)
+{
+    AppleHTTPContext *s = h->priv_data;
+    int ret, i;
+    const char *nested_url;
+
+    if (flags & AVIO_FLAG_WRITE)
+        return AVERROR(ENOSYS);
+
+    h->is_streamed = 1;
+
+    if (av_strstart(uri, "hls+", &nested_url)) {
+        av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
+    } else if (av_strstart(uri, "hls://", &nested_url)) {
+        av_log(h, AV_LOG_ERROR,
+               "No nested protocol specified. Specify e.g. hls+http://%s\n",
+               nested_url);
+        ret = AVERROR(EINVAL);
+        goto fail;
+#if FF_API_APPLEHTTP_PROTO
+    } else if (av_strstart(uri, "applehttp+", &nested_url)) {
+        av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
+        av_log(h, AV_LOG_WARNING,
+               "The applehttp protocol is deprecated, use hls+%s as url "
+               "instead.\n", nested_url);
+    } else if (av_strstart(uri, "applehttp://", &nested_url)) {
+        av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
+        av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
+        av_log(h, AV_LOG_WARNING,
+               "The applehttp protocol is deprecated, use hls+http://%s as url "
+               "instead.\n", nested_url);
+#endif
+    } else {
+        av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
+        ret = AVERROR(EINVAL);
+        goto fail;
+    }
+
+    if ((ret = parse_playlist(h, s->playlisturl)) < 0)
+        goto fail;
+
+    if (s->n_segments == 0 && s->n_variants > 0) {
+        int max_bandwidth = 0, maxvar = -1;
+        for (i = 0; i < s->n_variants; i++) {
+            if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
+                max_bandwidth = s->variants[i]->bandwidth;
+                maxvar = i;
+            }
+        }
+        av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
+                   sizeof(s->playlisturl));
+        if ((ret = parse_playlist(h, s->playlisturl)) < 0)
+            goto fail;
+    }
+
+    if (s->n_segments == 0) {
+        av_log(h, AV_LOG_WARNING, "Empty playlist\n");
+        ret = AVERROR(EIO);
+        goto fail;
+    }
+    s->cur_seq_no = s->start_seq_no;
+    if (!s->finished && s->n_segments >= 3)
+        s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
+
+    return 0;
+
+fail:
+    applehttp_close(h);
+    return ret;
+}
+
+static int applehttp_read(URLContext *h, uint8_t *buf, int size)
+{
+    AppleHTTPContext *s = h->priv_data;
+    const char *url;
+    int ret;
+    int64_t reload_interval;
+
+start:
+    if (s->seg_hd) {
+        ret = ffurl_read(s->seg_hd, buf, size);
+        if (ret > 0)
+            return ret;
+    }
+    if (s->seg_hd) {
+        ffurl_close(s->seg_hd);
+        s->seg_hd = NULL;
+        s->cur_seq_no++;
+    }
+    reload_interval = s->n_segments > 0 ?
+                      s->segments[s->n_segments - 1]->duration :
+                      s->target_duration;
+    reload_interval *= 1000000;
+retry:
+    if (!s->finished) {
+        int64_t now = av_gettime();
+        if (now - s->last_load_time >= reload_interval) {
+            if ((ret = parse_playlist(h, s->playlisturl)) < 0)
+                return ret;
+            /* If we need to reload the playlist again below (if
+             * there's still no more segments), switch to a reload
+             * interval of half the target duration. */
+            reload_interval = s->target_duration * 500000;
+        }
+    }
+    if (s->cur_seq_no < s->start_seq_no) {
+        av_log(h, AV_LOG_WARNING,
+               "skipping %d segments ahead, expired from playlist\n",
+               s->start_seq_no - s->cur_seq_no);
+        s->cur_seq_no = s->start_seq_no;
+    }
+    if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
+        if (s->finished)
+            return AVERROR_EOF;
+        while (av_gettime() - s->last_load_time < reload_interval) {
+            if (ff_check_interrupt(&h->interrupt_callback))
+                return AVERROR_EXIT;
+            usleep(100*1000);
+        }
+        goto retry;
+    }
+    url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
+    av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
+    ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,
+                     &h->interrupt_callback, NULL);
+    if (ret < 0) {
+        if (ff_check_interrupt(&h->interrupt_callback))
+            return AVERROR_EXIT;
+        av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
+        s->cur_seq_no++;
+        goto retry;
+    }
+    goto start;
+}
+
+#if FF_API_APPLEHTTP_PROTO
+URLProtocol ff_applehttp_protocol = {
+    .name           = "applehttp",
+    .url_open       = applehttp_open,
+    .url_read       = applehttp_read,
+    .url_close      = applehttp_close,
+    .flags          = URL_PROTOCOL_FLAG_NESTED_SCHEME,
+    .priv_data_size = sizeof(AppleHTTPContext),
+};
+#endif
+
+URLProtocol ff_hls_protocol = {
+    .name           = "hls",
+    .url_open       = applehttp_open,
+    .url_read       = applehttp_read,
+    .url_close      = applehttp_close,
+    .flags          = URL_PROTOCOL_FLAG_NESTED_SCHEME,
+    .priv_data_size = sizeof(AppleHTTPContext),
+};