mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2024-11-09 19:09:41 +00:00
Code Issues 1 Projects Releases Wiki Activity
gstreamer/ext/hls/gsthlsdemux.c
Sebastian Dröge b3a7242910 hlsdemux: Keep track of timestamps by adding them up during playback 
...instead of adding them from the start of playlist every time. This
among other things fixes timestamps for live streams, where the playlist
is some kind of ringbuffer of fragments and thus adding from the beginning
of the playlist will miss the past fragments.

https://bugzilla.gnome.org/show_bug.cgi?id=724983
2014-02-23 15:18:22 +01:00

1443 lines
43 KiB
C
Raw Blame History

/* GStreamer
* Copyright (C) 2010 Marc-Andre Lureau <marcandre.lureau@gmail.com>
* Copyright (C) 2010 Andoni Morales Alastruey <ylatuya@gmail.com>
* Copyright (C) 2011, Hewlett-Packard Development Company, L.P.
* Author: Youness Alaoui <youness.alaoui@collabora.co.uk>, Collabora Ltd.
* Author: Sebastian Dröge <sebastian.droege@collabora.co.uk>, Collabora Ltd.
* Copyright (C) 2014 Sebastian Dröge <sebastian@centricular.com>
*
* Gsthlsdemux.c:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:element-hlsdemux
*
* HTTP Live Streaming demuxer element.
*
* <refsect2>
* <title>Example launch line</title>
* |[
* gst-launch souphttpsrc location=http://devimages.apple.com/iphone/samples/bipbop/gear4/prog_index.m3u8 ! hlsdemux ! decodebin2 ! videoconvert ! videoscale ! autovideosink
* ]|
* </refsect2>
*
* Last reviewed on 2010-10-07
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <string.h>
#ifdef HAVE_NETTLE
#include <nettle/aes.h>
#include <nettle/cbc.h>
#else
#include <gcrypt.h>
#endif
#include "gsthlsdemux.h"
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src_%u",
GST_PAD_SRC,
GST_PAD_SOMETIMES,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-hls"));
GST_DEBUG_CATEGORY_STATIC (gst_hls_demux_debug);
#define GST_CAT_DEFAULT gst_hls_demux_debug
enum
{
PROP_0,
PROP_FRAGMENTS_CACHE,
PROP_BITRATE_LIMIT,
PROP_CONNECTION_SPEED,
PROP_LAST
};
#define DEFAULT_FRAGMENTS_CACHE 1
#define DEFAULT_FAILED_COUNT 3
#define DEFAULT_BITRATE_LIMIT 0.8
#define DEFAULT_CONNECTION_SPEED 0
/* GObject */
static void gst_hls_demux_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_hls_demux_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static void gst_hls_demux_dispose (GObject * obj);
/* GstElement */
static GstStateChangeReturn
gst_hls_demux_change_state (GstElement * element, GstStateChange transition);
/* GstHLSDemux */
static GstFlowReturn gst_hls_demux_chain (GstPad * pad, GstObject * parent,
GstBuffer * buf);
static gboolean gst_hls_demux_sink_event (GstPad * pad, GstObject * parent,
GstEvent * event);
static gboolean gst_hls_demux_src_event (GstPad * pad, GstObject * parent,
GstEvent * event);
static gboolean gst_hls_demux_src_query (GstPad * pad, GstObject * parent,
GstQuery * query);
static void gst_hls_demux_stream_loop (GstHLSDemux * demux);
static void gst_hls_demux_updates_loop (GstHLSDemux * demux);
static void gst_hls_demux_stop (GstHLSDemux * demux);
static void gst_hls_demux_pause_tasks (GstHLSDemux * demux);
static gboolean gst_hls_demux_switch_playlist (GstHLSDemux * demux,
GstFragment * fragment);
static GstFragment *gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
gboolean * end_of_playlist, GError ** err);
static gboolean gst_hls_demux_update_playlist (GstHLSDemux * demux,
gboolean update, GError ** err);
static void gst_hls_demux_reset (GstHLSDemux * demux, gboolean dispose);
static gboolean gst_hls_demux_set_location (GstHLSDemux * demux,
const gchar * uri);
static gchar *gst_hls_src_buf_to_utf8_playlist (GstBuffer * buf);
#define gst_hls_demux_parent_class parent_class
G_DEFINE_TYPE (GstHLSDemux, gst_hls_demux, GST_TYPE_ELEMENT);
static void
gst_hls_demux_dispose (GObject * obj)
{
GstHLSDemux *demux = GST_HLS_DEMUX (obj);
if (demux->stream_task) {
gst_object_unref (demux->stream_task);
g_rec_mutex_clear (&demux->stream_lock);
demux->stream_task = NULL;
}
if (demux->updates_task) {
gst_object_unref (demux->updates_task);
g_rec_mutex_clear (&demux->updates_lock);
demux->updates_task = NULL;
}
if (demux->downloader != NULL) {
g_object_unref (demux->downloader);
demux->downloader = NULL;
}
gst_hls_demux_reset (demux, TRUE);
g_mutex_clear (&demux->download_lock);
g_cond_clear (&demux->download_cond);
g_cond_clear (&demux->updates_timed_cond);
G_OBJECT_CLASS (parent_class)->dispose (obj);
}
static void
gst_hls_demux_class_init (GstHLSDemuxClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *element_class;
gobject_class = (GObjectClass *) klass;
element_class = (GstElementClass *) klass;
gobject_class->set_property = gst_hls_demux_set_property;
gobject_class->get_property = gst_hls_demux_get_property;
gobject_class->dispose = gst_hls_demux_dispose;
g_object_class_install_property (gobject_class, PROP_FRAGMENTS_CACHE,
g_param_spec_uint ("fragments-cache", "Fragments cache",
"Number of fragments needed to be cached to start playing "
"(DEPRECATED: Has no effect since 1.3.1)",
1, G_MAXUINT, DEFAULT_FRAGMENTS_CACHE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_BITRATE_LIMIT,
g_param_spec_float ("bitrate-limit",
"Bitrate limit in %",
"Limit of the available bitrate to use when switching to alternates.",
0, 1, DEFAULT_BITRATE_LIMIT,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
g_object_class_install_property (gobject_class, PROP_CONNECTION_SPEED,
g_param_spec_uint ("connection-speed", "Connection Speed",
"Network connection speed in kbps (0 = unknown)",
0, G_MAXUINT / 1000, DEFAULT_CONNECTION_SPEED,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
element_class->change_state = GST_DEBUG_FUNCPTR (gst_hls_demux_change_state);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&srctemplate));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sinktemplate));
gst_element_class_set_static_metadata (element_class,
"HLS Demuxer",
"Codec/Demuxer/Adaptive",
"HTTP Live Streaming demuxer",
"Marc-Andre Lureau <marcandre.lureau@gmail.com>\n"
"Andoni Morales Alastruey <ylatuya@gmail.com>");
GST_DEBUG_CATEGORY_INIT (gst_hls_demux_debug, "hlsdemux", 0,
"hlsdemux element");
}
static void
gst_hls_demux_init (GstHLSDemux * demux)
{
/* sink pad */
demux->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");
gst_pad_set_chain_function (demux->sinkpad,
GST_DEBUG_FUNCPTR (gst_hls_demux_chain));
gst_pad_set_event_function (demux->sinkpad,
GST_DEBUG_FUNCPTR (gst_hls_demux_sink_event));
gst_element_add_pad (GST_ELEMENT (demux), demux->sinkpad);
/* Downloader */
demux->downloader = gst_uri_downloader_new ();
demux->do_typefind = TRUE;
/* Properties */
demux->bitrate_limit = DEFAULT_BITRATE_LIMIT;
demux->connection_speed = DEFAULT_CONNECTION_SPEED;
g_mutex_init (&demux->download_lock);
g_cond_init (&demux->download_cond);
g_cond_init (&demux->updates_timed_cond);
/* Updates task */
g_rec_mutex_init (&demux->updates_lock);
demux->updates_task =
gst_task_new ((GstTaskFunction) gst_hls_demux_updates_loop, demux, NULL);
gst_task_set_lock (demux->updates_task, &demux->updates_lock);
/* Streaming task */
g_rec_mutex_init (&demux->stream_lock);
demux->stream_task =
gst_task_new ((GstTaskFunction) gst_hls_demux_stream_loop, demux, NULL);
gst_task_set_lock (demux->stream_task, &demux->stream_lock);
demux->have_group_id = FALSE;
demux->group_id = G_MAXUINT;
}
static void
gst_hls_demux_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstHLSDemux *demux = GST_HLS_DEMUX (object);
switch (prop_id) {
case PROP_FRAGMENTS_CACHE:
break;
case PROP_BITRATE_LIMIT:
demux->bitrate_limit = g_value_get_float (value);
break;
case PROP_CONNECTION_SPEED:
demux->connection_speed = g_value_get_uint (value) * 1000;
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_hls_demux_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstHLSDemux *demux = GST_HLS_DEMUX (object);
switch (prop_id) {
case PROP_FRAGMENTS_CACHE:
g_value_set_uint (value, 1);
break;
case PROP_BITRATE_LIMIT:
g_value_set_float (value, demux->bitrate_limit);
break;
case PROP_CONNECTION_SPEED:
g_value_set_uint (value, demux->connection_speed / 1000);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static GstStateChangeReturn
gst_hls_demux_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret;
GstHLSDemux *demux = GST_HLS_DEMUX (element);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_PAUSED:
gst_hls_demux_reset (demux, FALSE);
gst_uri_downloader_reset (demux->downloader);
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
switch (transition) {
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_hls_demux_stop (demux);
gst_task_join (demux->updates_task);
gst_task_join (demux->stream_task);
gst_hls_demux_reset (demux, FALSE);
break;
default:
break;
}
return ret;
}
static gboolean
gst_hls_demux_src_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstHLSDemux *demux;
demux = GST_HLS_DEMUX (parent);
switch (event->type) {
case GST_EVENT_SEEK:
{
gdouble rate;
GstFormat format;
GstSeekFlags flags;
GstSeekType start_type, stop_type;
gint64 start, stop;
GList *walk;
GstClockTime current_pos, target_pos;
gint current_sequence;
GstM3U8MediaFile *file;
GST_INFO_OBJECT (demux, "Received GST_EVENT_SEEK");
if (gst_m3u8_client_is_live (demux->client)) {
GST_WARNING_OBJECT (demux, "Received seek event for live stream");
return FALSE;
}
gst_event_parse_seek (event, &rate, &format, &flags, &start_type, &start,
&stop_type, &stop);
if (format != GST_FORMAT_TIME)
return FALSE;
GST_DEBUG_OBJECT (demux, "seek event, rate: %f start: %" GST_TIME_FORMAT
" stop: %" GST_TIME_FORMAT, rate, GST_TIME_ARGS (start),
GST_TIME_ARGS (stop));
GST_M3U8_CLIENT_LOCK (demux->client);
file = GST_M3U8_MEDIA_FILE (demux->client->current->files->data);
current_sequence = file->sequence;
current_pos = 0;
target_pos = (GstClockTime) start;
for (walk = demux->client->current->files; walk; walk = walk->next) {
file = walk->data;
current_sequence = file->sequence;
if (current_pos <= target_pos
&& target_pos < current_pos + file->duration) {
break;
}
current_pos += file->duration;
}
GST_M3U8_CLIENT_UNLOCK (demux->client);
if (walk == NULL) {
GST_WARNING_OBJECT (demux, "Could not find seeked fragment");
return FALSE;
}
if (flags & GST_SEEK_FLAG_FLUSH) {
GST_DEBUG_OBJECT (demux, "sending flush start");
gst_pad_push_event (demux->srcpad, gst_event_new_flush_start ());
}
gst_hls_demux_pause_tasks (demux);
/* wait for streaming to finish */
g_rec_mutex_lock (&demux->updates_lock);
g_rec_mutex_unlock (&demux->updates_lock);
g_rec_mutex_lock (&demux->stream_lock);
GST_M3U8_CLIENT_LOCK (demux->client);
GST_DEBUG_OBJECT (demux, "seeking to sequence %d", current_sequence);
demux->client->sequence = current_sequence;
demux->client->sequence_position = current_pos;
demux->position_shift = start - current_pos;
demux->need_segment = TRUE;
GST_M3U8_CLIENT_UNLOCK (demux->client);
if (flags & GST_SEEK_FLAG_FLUSH) {
GST_DEBUG_OBJECT (demux, "sending flush stop");
gst_pad_push_event (demux->srcpad, gst_event_new_flush_stop (TRUE));
}
demux->stop_updates_task = FALSE;
gst_uri_downloader_reset (demux->downloader);
demux->stop_stream_task = FALSE;
gst_task_start (demux->updates_task);
g_rec_mutex_unlock (&demux->stream_lock);
return TRUE;
}
default:
break;
}
return gst_pad_event_default (pad, parent, event);
}
static gboolean
gst_hls_demux_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstHLSDemux *demux;
GstQuery *query;
gboolean ret;
gchar *uri;
demux = GST_HLS_DEMUX (parent);
switch (event->type) {
case GST_EVENT_EOS:{
gchar *playlist = NULL;
if (demux->playlist == NULL) {
GST_WARNING_OBJECT (demux, "Received EOS without a playlist.");
break;
}
GST_DEBUG_OBJECT (demux,
"Got EOS on the sink pad: main playlist fetched");
query = gst_query_new_uri ();
ret = gst_pad_peer_query (demux->sinkpad, query);
if (ret) {
gst_query_parse_uri_redirection (query, &uri);
if (uri == NULL)
gst_query_parse_uri (query, &uri);
gst_hls_demux_set_location (demux, uri);
g_free (uri);
}
gst_query_unref (query);
playlist = gst_hls_src_buf_to_utf8_playlist (demux->playlist);
demux->playlist = NULL;
if (playlist == NULL) {
GST_WARNING_OBJECT (demux, "Error validating first playlist.");
} else if (!gst_m3u8_client_update (demux->client, playlist)) {
/* In most cases, this will happen if we set a wrong url in the
* source element and we have received the 404 HTML response instead of
* the playlist */
GST_ELEMENT_ERROR (demux, STREAM, DECODE, ("Invalid playlist."),
(NULL));
return FALSE;
}
if (!ret && gst_m3u8_client_is_live (demux->client)) {
GST_ELEMENT_ERROR (demux, RESOURCE, NOT_FOUND,
("Failed querying the playlist uri, "
"required for live sources."), (NULL));
return FALSE;
}
gst_task_start (demux->updates_task);
gst_event_unref (event);
return TRUE;
}
case GST_EVENT_SEGMENT:
/* Swallow newsegments, we'll push our own */
gst_event_unref (event);
return TRUE;
default:
break;
}
return gst_pad_event_default (pad, parent, event);
}
static gboolean
gst_hls_demux_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
GstHLSDemux *hlsdemux;
gboolean ret = FALSE;
if (query == NULL)
return FALSE;
hlsdemux = GST_HLS_DEMUX (parent);
switch (query->type) {
case GST_QUERY_DURATION:{
GstClockTime duration = -1;
GstFormat fmt;
gst_query_parse_duration (query, &fmt, NULL);
if (fmt == GST_FORMAT_TIME) {
duration = gst_m3u8_client_get_duration (hlsdemux->client);
if (GST_CLOCK_TIME_IS_VALID (duration) && duration > 0) {
gst_query_set_duration (query, GST_FORMAT_TIME, duration);
ret = TRUE;
}
}
GST_INFO_OBJECT (hlsdemux, "GST_QUERY_DURATION returns %s with duration %"
GST_TIME_FORMAT, ret ? "TRUE" : "FALSE", GST_TIME_ARGS (duration));
break;
}
case GST_QUERY_URI:
if (hlsdemux->client) {
/* FIXME: Do we answer with the variant playlist, with the current
* playlist or the the uri of the least downlowaded fragment? */
gst_query_set_uri (query, gst_m3u8_client_get_uri (hlsdemux->client));
ret = TRUE;
}
break;
case GST_QUERY_SEEKING:{
GstFormat fmt;
gint64 stop = -1;
gst_query_parse_seeking (query, &fmt, NULL, NULL, NULL);
GST_INFO_OBJECT (hlsdemux, "Received GST_QUERY_SEEKING with format %d",
fmt);
if (fmt == GST_FORMAT_TIME) {
GstClockTime duration;
duration = gst_m3u8_client_get_duration (hlsdemux->client);
if (GST_CLOCK_TIME_IS_VALID (duration) && duration > 0)
stop = duration;
gst_query_set_seeking (query, fmt,
!gst_m3u8_client_is_live (hlsdemux->client), 0, stop);
ret = TRUE;
GST_INFO_OBJECT (hlsdemux, "GST_QUERY_SEEKING returning with stop : %"
GST_TIME_FORMAT, GST_TIME_ARGS (stop));
}
break;
}
default:
/* Don't fordward queries upstream because of the special nature of this
* "demuxer", which relies on the upstream element only to be fed with the
* first playlist */
break;
}
return ret;
}
static GstFlowReturn
gst_hls_demux_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
GstHLSDemux *demux = GST_HLS_DEMUX (parent);
if (demux->playlist == NULL)
demux->playlist = buf;
else
demux->playlist = gst_buffer_append (demux->playlist, buf);
return GST_FLOW_OK;
}
static void
gst_hls_demux_pause_tasks (GstHLSDemux * demux)
{
if (GST_TASK_STATE (demux->updates_task) != GST_TASK_STOPPED) {
g_mutex_lock (&demux->updates_timed_lock);
demux->stop_updates_task = TRUE;
g_cond_signal (&demux->updates_timed_cond);
g_mutex_unlock (&demux->updates_timed_lock);
gst_uri_downloader_cancel (demux->downloader);
gst_task_pause (demux->updates_task);
}
if (GST_TASK_STATE (demux->stream_task) != GST_TASK_STOPPED) {
g_mutex_lock (&demux->download_lock);
demux->stop_stream_task = TRUE;
g_cond_signal (&demux->download_cond);
g_mutex_unlock (&demux->download_lock);
gst_task_pause (demux->stream_task);
}
}
static void
gst_hls_demux_stop (GstHLSDemux * demux)
{
if (GST_TASK_STATE (demux->updates_task) != GST_TASK_STOPPED) {
g_mutex_lock (&demux->updates_timed_lock);
demux->stop_updates_task = TRUE;
g_cond_signal (&demux->updates_timed_cond);
g_mutex_unlock (&demux->updates_timed_lock);
gst_uri_downloader_cancel (demux->downloader);
gst_task_stop (demux->updates_task);
g_rec_mutex_lock (&demux->updates_lock);
g_rec_mutex_unlock (&demux->updates_lock);
}
if (GST_TASK_STATE (demux->stream_task) != GST_TASK_STOPPED) {
g_mutex_lock (&demux->download_lock);
demux->stop_stream_task = TRUE;
g_cond_signal (&demux->download_cond);
g_mutex_unlock (&demux->download_lock);
gst_task_stop (demux->stream_task);
g_rec_mutex_lock (&demux->stream_lock);
g_rec_mutex_unlock (&demux->stream_lock);
}
}
static void
switch_pads (GstHLSDemux * demux, GstCaps * newcaps)
{
GstPad *oldpad = demux->srcpad;
GstEvent *event;
gchar *stream_id;
gchar *name;
GST_DEBUG ("Switching pads (oldpad:%p) with caps: %" GST_PTR_FORMAT, oldpad,
newcaps);
/* First create and activate new pad */
name = g_strdup_printf ("src_%u", demux->srcpad_counter++);
demux->srcpad = gst_pad_new_from_static_template (&srctemplate, name);
g_free (name);
gst_pad_set_event_function (demux->srcpad,
GST_DEBUG_FUNCPTR (gst_hls_demux_src_event));
gst_pad_set_query_function (demux->srcpad,
GST_DEBUG_FUNCPTR (gst_hls_demux_src_query));
gst_pad_use_fixed_caps (demux->srcpad);
gst_pad_set_active (demux->srcpad, TRUE);
stream_id =
gst_pad_create_stream_id (demux->srcpad, GST_ELEMENT_CAST (demux), NULL);
event = gst_pad_get_sticky_event (demux->sinkpad, GST_EVENT_STREAM_START, 0);
if (event) {
if (gst_event_parse_group_id (event, &demux->group_id))
demux->have_group_id = TRUE;
else
demux->have_group_id = FALSE;
gst_event_unref (event);
} else if (!demux->have_group_id) {
demux->have_group_id = TRUE;
demux->group_id = gst_util_group_id_next ();
}
event = gst_event_new_stream_start (stream_id);
if (demux->have_group_id)
gst_event_set_group_id (event, demux->group_id);
gst_pad_push_event (demux->srcpad, event);
g_free (stream_id);
gst_pad_set_caps (demux->srcpad, newcaps);
gst_element_add_pad (GST_ELEMENT (demux), demux->srcpad);
gst_element_no_more_pads (GST_ELEMENT (demux));
if (oldpad) {
/* Push out EOS */
gst_pad_push_event (oldpad, gst_event_new_eos ());
gst_pad_set_active (oldpad, FALSE);
gst_element_remove_pad (GST_ELEMENT (demux), oldpad);
}
}
static void
gst_hls_demux_stream_loop (GstHLSDemux * demux)
{
GstFragment *fragment;
GstBuffer *buf;
GstFlowReturn ret;
GstCaps *bufcaps, *srccaps = NULL;
gboolean end_of_playlist;
GError *err = NULL;
/* This task will download fragments as fast as possible, sends
* SEGMENT and CAPS events and switches pads if necessary.
* If downloading a fragment fails we try again up to 3 times
* after waiting a bit. If we're at the end of the playlist
* we wait for the playlist to update before getting the next
* fragment.
*/
GST_DEBUG_OBJECT (demux, "Enter task");
if (demux->stop_stream_task)
goto pause_task;
demux->next_download = g_get_monotonic_time ();
if ((fragment =
gst_hls_demux_get_next_fragment (demux, &end_of_playlist,
&err)) == NULL) {
if (demux->stop_stream_task) {
g_clear_error (&err);
goto pause_task;
}
if (end_of_playlist) {
if (!gst_m3u8_client_is_live (demux->client)) {
GST_DEBUG_OBJECT (demux, "End of playlist");
demux->end_of_playlist = TRUE;
goto end_of_playlist;
} else {
g_mutex_lock (&demux->download_lock);
/* Wait until we're cancelled or there's something for
* us to download in the playlist or the playlist
* became non-live */
while (TRUE) {
if (demux->stop_stream_task) {
g_mutex_unlock (&demux->download_lock);
goto pause_task;
}
/* Got a new fragment or not live anymore? */
if (gst_m3u8_client_get_next_fragment (demux->client, NULL, NULL,
NULL, NULL, NULL, NULL)
|| !gst_m3u8_client_is_live (demux->client))
break;
GST_DEBUG_OBJECT (demux,
"No fragment left but live playlist, wait a bit");
g_cond_wait (&demux->download_cond, &demux->download_lock);
}
g_mutex_unlock (&demux->download_lock);
GST_DEBUG_OBJECT (demux, "Retrying now");
return;
}
} else {
demux->download_failed_count++;
if (demux->download_failed_count < DEFAULT_FAILED_COUNT) {
GST_WARNING_OBJECT (demux, "Could not fetch the next fragment");
g_clear_error (&err);
/* Wait half the fragment duration before retrying */
demux->next_download +=
gst_util_uint64_scale (gst_m3u8_client_get_current_fragment_duration
(demux->client), G_USEC_PER_SEC, 2 * GST_SECOND);
g_mutex_lock (&demux->download_lock);
if (demux->stop_stream_task) {
g_mutex_unlock (&demux->download_lock);
goto pause_task;
}
g_cond_wait_until (&demux->download_cond, &demux->download_lock,
demux->next_download);
g_mutex_unlock (&demux->download_lock);
GST_DEBUG_OBJECT (demux, "Retrying now");
return;
} else {
gst_element_post_message (GST_ELEMENT_CAST (demux),
gst_message_new_error (GST_OBJECT_CAST (demux), err,
"Could not fetch the next fragment"));
g_clear_error (&err);
goto pause_task;
}
}
} else {
demux->download_failed_count = 0;
gst_m3u8_client_advance_fragment (demux->client);
if (demux->stop_updates_task) {
g_object_unref (fragment);
goto pause_task;
}
/* try to switch to another bitrate if needed */
gst_hls_demux_switch_playlist (demux, fragment);
}
if (demux->stop_updates_task) {
g_object_unref (fragment);
goto pause_task;
}
/* Figure out if we need to create/switch pads */
if (G_LIKELY (demux->srcpad))
srccaps = gst_pad_get_current_caps (demux->srcpad);
bufcaps = gst_fragment_get_caps (fragment);
if (G_UNLIKELY (!bufcaps)) {
if (srccaps)
gst_caps_unref (srccaps);
g_object_unref (fragment);
goto type_not_found;
}
buf = gst_fragment_get_buffer (fragment);
if (G_UNLIKELY (!srccaps || !gst_caps_is_equal_fixed (bufcaps, srccaps))) {
switch_pads (demux, bufcaps);
demux->need_segment = TRUE;
}
gst_caps_unref (bufcaps);
if (G_LIKELY (srccaps))
gst_caps_unref (srccaps);
g_object_unref (fragment);
if (demux->need_segment) {
GstSegment segment;
GstClockTime start = GST_BUFFER_PTS (buf);
start += demux->position_shift;
/* And send a newsegment */
GST_DEBUG_OBJECT (demux, "Sending new-segment. segment start:%"
GST_TIME_FORMAT, GST_TIME_ARGS (start));
gst_segment_init (&segment, GST_FORMAT_TIME);
segment.start = start;
segment.time = start;
gst_pad_push_event (demux->srcpad, gst_event_new_segment (&segment));
demux->need_segment = FALSE;
demux->position_shift = 0;
}
GST_DEBUG_OBJECT (demux, "Pushing buffer %" GST_TIME_FORMAT,
GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)));
ret = gst_pad_push (demux->srcpad, buf);
if (ret != GST_FLOW_OK)
goto error_pushing;
GST_DEBUG_OBJECT (demux, "Pushed buffer");
return;
end_of_playlist:
{
GST_DEBUG_OBJECT (demux, "Reached end of playlist, sending EOS");
gst_pad_push_event (demux->srcpad, gst_event_new_eos ());
gst_hls_demux_pause_tasks (demux);
return;
}
type_not_found:
{
GST_ELEMENT_ERROR (demux, STREAM, TYPE_NOT_FOUND,
("Could not determine type of stream"), (NULL));
gst_hls_demux_pause_tasks (demux);
return;
}
error_pushing:
{
if (ret == GST_FLOW_NOT_LINKED || ret < GST_FLOW_EOS) {
GST_ELEMENT_ERROR (demux, STREAM, FAILED, (NULL),
("stream stopped, reason %s", gst_flow_get_name (ret)));
gst_pad_push_event (demux->srcpad, gst_event_new_eos ());
} else {
GST_DEBUG_OBJECT (demux, "stream stopped, reason %s",
gst_flow_get_name (ret));
}
gst_hls_demux_pause_tasks (demux);
return;
}
pause_task:
{
GST_DEBUG_OBJECT (demux, "Pause task");
/* Pausing a stopped task will start it */
gst_hls_demux_pause_tasks (demux);
return;
}
}
static void
gst_hls_demux_reset (GstHLSDemux * demux, gboolean dispose)
{
demux->end_of_playlist = FALSE;
demux->stop_updates_task = FALSE;
demux->do_typefind = TRUE;
demux->download_failed_count = 0;
g_free (demux->key_url);
demux->key_url = NULL;
if (demux->key_fragment)
g_object_unref (demux->key_fragment);
demux->key_fragment = NULL;
if (demux->input_caps) {
gst_caps_unref (demux->input_caps);
demux->input_caps = NULL;
}
if (demux->playlist) {
gst_buffer_unref (demux->playlist);
demux->playlist = NULL;
}
if (demux->client) {
gst_m3u8_client_free (demux->client);
demux->client = NULL;
}
if (!dispose) {
demux->client = gst_m3u8_client_new ("");
}
demux->position_shift = 0;
demux->need_segment = TRUE;
demux->have_group_id = FALSE;
demux->group_id = G_MAXUINT;
demux->srcpad_counter = 0;
if (demux->srcpad) {
gst_element_remove_pad (GST_ELEMENT_CAST (demux), demux->srcpad);
demux->srcpad = NULL;
}
}
static gboolean
gst_hls_demux_set_location (GstHLSDemux * demux, const gchar * uri)
{
if (demux->client)
gst_m3u8_client_free (demux->client);
demux->client = gst_m3u8_client_new (uri);
GST_INFO_OBJECT (demux, "Changed location: %s", uri);
return TRUE;
}
void
gst_hls_demux_updates_loop (GstHLSDemux * demux)
{
/* Loop for updating of the playlist. This periodically checks if
* the playlist is updated and does so, then signals the streaming
* thread in case it can continue downloading now.
* For non-live playlists this thread is not doing much else than
* setting up the initial playlist and then stopping. */
/* block until the next scheduled update or the signal to quit this thread */
GST_DEBUG_OBJECT (demux, "Started updates task");
/* If this playlist is a variant playlist, select the first one
* and update it */
if (gst_m3u8_client_has_variant_playlist (demux->client)) {
GstM3U8 *child = NULL;
GError *err = NULL;
if (demux->connection_speed == 0) {
GST_M3U8_CLIENT_LOCK (demux->client);
child = demux->client->main->current_variant->data;
GST_M3U8_CLIENT_UNLOCK (demux->client);
} else {
GList *tmp = gst_m3u8_client_get_playlist_for_bitrate (demux->client,
demux->connection_speed);
child = GST_M3U8 (tmp->data);
}
gst_m3u8_client_set_current (demux->client, child);
if (!gst_hls_demux_update_playlist (demux, FALSE, &err)) {
gst_element_post_message (GST_ELEMENT_CAST (demux),
gst_message_new_error (GST_OBJECT_CAST (demux), err,
"Could not fetch the child playlist"));
g_error_free (err);
goto error;
}
}
if (!gst_m3u8_client_is_live (demux->client)) {
GstClockTime duration = gst_m3u8_client_get_duration (demux->client);
GST_DEBUG_OBJECT (demux, "Sending duration message : %" GST_TIME_FORMAT,
GST_TIME_ARGS (duration));
if (duration != GST_CLOCK_TIME_NONE)
gst_element_post_message (GST_ELEMENT (demux),
gst_message_new_duration_changed (GST_OBJECT (demux)));
}
/* Now start stream task */
gst_task_start (demux->stream_task);
demux->next_update =
g_get_monotonic_time () +
gst_util_uint64_scale (gst_m3u8_client_get_target_duration
(demux->client), G_USEC_PER_SEC, GST_SECOND);
/* Updating playlist only needed for live playlists */
while (gst_m3u8_client_is_live (demux->client)) {
GError *err = NULL;
/* Wait here until we should do the next update or we're cancelled */
GST_DEBUG_OBJECT (demux, "Wait for next playlist update");
g_mutex_lock (&demux->updates_timed_lock);
if (demux->stop_updates_task) {
g_mutex_unlock (&demux->updates_timed_lock);
goto quit;
}
g_cond_wait_until (&demux->updates_timed_cond, &demux->updates_timed_lock,
demux->next_update);
if (demux->stop_updates_task) {
g_mutex_unlock (&demux->updates_timed_lock);
goto quit;
}
g_mutex_unlock (&demux->updates_timed_lock);
GST_DEBUG_OBJECT (demux, "Updating playlist");
if (!gst_hls_demux_update_playlist (demux, TRUE, &err)) {
if (demux->stop_updates_task)
goto quit;
demux->client->update_failed_count++;
if (demux->client->update_failed_count < DEFAULT_FAILED_COUNT) {
GST_WARNING_OBJECT (demux, "Could not update the playlist");
demux->next_update =
g_get_monotonic_time () +
gst_util_uint64_scale (gst_m3u8_client_get_target_duration
(demux->client), G_USEC_PER_SEC, 2 * GST_SECOND);
} else {
gst_element_post_message (GST_ELEMENT_CAST (demux),
gst_message_new_error (GST_OBJECT_CAST (demux), err,
"Could not update the playlist"));
g_error_free (err);
goto error;
}
} else {
GST_DEBUG_OBJECT (demux, "Updated playlist successfully");
demux->next_update =
g_get_monotonic_time () +
gst_util_uint64_scale (gst_m3u8_client_get_target_duration
(demux->client), G_USEC_PER_SEC, GST_SECOND);
/* Wake up download task */
g_mutex_lock (&demux->download_lock);
g_cond_signal (&demux->download_cond);
g_mutex_unlock (&demux->download_lock);
}
}
quit:
{
GST_DEBUG_OBJECT (demux, "Stopped updates task");
gst_task_pause (demux->updates_task);
return;
}
error:
{
GST_DEBUG_OBJECT (demux, "Stopped updates task because of error");
gst_hls_demux_pause_tasks (demux);
}
}
static gchar *
gst_hls_src_buf_to_utf8_playlist (GstBuffer * buf)
{
GstMapInfo info;
gchar *playlist;
if (!gst_buffer_map (buf, &info, GST_MAP_READ))
goto map_error;
if (!g_utf8_validate ((gchar *) info.data, info.size, NULL))
goto validate_error;
/* alloc size + 1 to end with a null character */
playlist = g_malloc0 (info.size + 1);
memcpy (playlist, info.data, info.size);
gst_buffer_unmap (buf, &info);
gst_buffer_unref (buf);
return playlist;
validate_error:
gst_buffer_unmap (buf, &info);
map_error:
gst_buffer_unref (buf);
return NULL;
}
static gboolean
gst_hls_demux_update_playlist (GstHLSDemux * demux, gboolean update,
GError ** err)
{
GstFragment *download;
GstBuffer *buf;
gchar *playlist;
gboolean updated = FALSE;
const gchar *uri = gst_m3u8_client_get_current_uri (demux->client);
download = gst_uri_downloader_fetch_uri (demux->downloader, uri, TRUE, err);
if (download == NULL)
return FALSE;
buf = gst_fragment_get_buffer (download);
playlist = gst_hls_src_buf_to_utf8_playlist (buf);
g_object_unref (download);
if (playlist == NULL) {
GST_WARNING_OBJECT (demux, "Couldn't validate playlist encoding");
g_set_error (err, GST_STREAM_ERROR, GST_STREAM_ERROR_WRONG_TYPE,
"Couldn't validate playlist encoding");
return FALSE;
}
updated = gst_m3u8_client_update (demux->client, playlist);
if (!updated) {
GST_WARNING_OBJECT (demux, "Couldn't update playlist");
g_set_error (err, GST_STREAM_ERROR, GST_STREAM_ERROR_FAILED,
"Couldn't update playlist");
return FALSE;
}
/* If it's a live source, do not let the sequence number go beyond
* three fragments before the end of the list */
if (updated && update == FALSE && demux->client->current &&
gst_m3u8_client_is_live (demux->client)) {
guint last_sequence;
GST_M3U8_CLIENT_LOCK (demux->client);
last_sequence =
GST_M3U8_MEDIA_FILE (g_list_last (demux->client->current->
files)->data)->sequence;
if (demux->client->sequence >= last_sequence - 3) {
GST_DEBUG_OBJECT (demux, "Sequence is beyond playlist. Moving back to %d",
last_sequence - 3);
demux->need_segment = TRUE;
demux->client->sequence = last_sequence - 3;
}
GST_M3U8_CLIENT_UNLOCK (demux->client);
}
return updated;
}
static gboolean
gst_hls_demux_change_playlist (GstHLSDemux * demux, guint max_bitrate)
{
GList *previous_variant, *current_variant;
gint old_bandwidth, new_bandwidth;
/* If user specifies a connection speed never use a playlist with a bandwidth
* superior than it */
if (demux->connection_speed != 0 && max_bitrate > demux->connection_speed)
max_bitrate = demux->connection_speed;
previous_variant = demux->client->main->current_variant;
current_variant = gst_m3u8_client_get_playlist_for_bitrate (demux->client,
max_bitrate);
retry_failover_protection:
old_bandwidth = GST_M3U8 (previous_variant->data)->bandwidth;
new_bandwidth = GST_M3U8 (current_variant->data)->bandwidth;
/* Don't do anything else if the playlist is the same */
if (new_bandwidth == old_bandwidth) {
return TRUE;
}
demux->client->main->current_variant = current_variant;
GST_M3U8_CLIENT_UNLOCK (demux->client);
gst_m3u8_client_set_current (demux->client, current_variant->data);
GST_INFO_OBJECT (demux, "Client was on %dbps, max allowed is %dbps, switching"
" to bitrate %dbps", old_bandwidth, max_bitrate, new_bandwidth);
if (gst_hls_demux_update_playlist (demux, FALSE, NULL)) {
GstStructure *s;
s = gst_structure_new ("playlist",
"uri", G_TYPE_STRING, gst_m3u8_client_get_current_uri (demux->client),
"bitrate", G_TYPE_INT, new_bandwidth, NULL);
gst_element_post_message (GST_ELEMENT_CAST (demux),
gst_message_new_element (GST_OBJECT_CAST (demux), s));
} else {
GList *failover = NULL;
GST_INFO_OBJECT (demux, "Unable to update playlist. Switching back");
GST_M3U8_CLIENT_LOCK (demux->client);
failover = g_list_previous (current_variant);
if (failover && new_bandwidth == GST_M3U8 (failover->data)->bandwidth) {
current_variant = failover;
goto retry_failover_protection;
}
demux->client->main->current_variant = previous_variant;
GST_M3U8_CLIENT_UNLOCK (demux->client);
gst_m3u8_client_set_current (demux->client, previous_variant->data);
/* Try a lower bitrate (or stop if we just tried the lowest) */
if (new_bandwidth ==
GST_M3U8 (g_list_first (demux->client->main->lists)->data)->bandwidth)
return FALSE;
else
return gst_hls_demux_change_playlist (demux, new_bandwidth - 1);
}
/* Force typefinding since we might have changed media type */
demux->do_typefind = TRUE;
return TRUE;
}
static gboolean
gst_hls_demux_switch_playlist (GstHLSDemux * demux, GstFragment * fragment)
{
GstClockTime diff;
gsize size;
gint bitrate;
GstBuffer *buffer;
GST_M3U8_CLIENT_LOCK (demux->client);
if (!demux->client->main->lists || !fragment) {
GST_M3U8_CLIENT_UNLOCK (demux->client);
return TRUE;
}
GST_M3U8_CLIENT_UNLOCK (demux->client);
/* compare the time when the fragment was downloaded with the time when it was
* scheduled */
diff = g_get_monotonic_time () - demux->next_download;
buffer = gst_fragment_get_buffer (fragment);
size = gst_buffer_get_size (buffer);
bitrate = (size * 8) / ((double) diff / G_USEC_PER_SEC);
GST_DEBUG ("Downloaded %d bytes in %" GST_TIME_FORMAT ". Bitrate is : %d",
(guint) size, GST_TIME_ARGS (diff * GST_USECOND), bitrate);
gst_buffer_unref (buffer);
return gst_hls_demux_change_playlist (demux, bitrate * demux->bitrate_limit);
}
#ifdef HAVE_NETTLE
static gboolean
decrypt_fragment (GstHLSDemux * demux, gsize length,
const guint8 * encrypted_data, guint8 * decrypted_data,
const guint8 * key_data, const guint8 * iv_data)
{
struct CBC_CTX (struct aes_ctx, AES_BLOCK_SIZE) aes_ctx;
if (length % 16 != 0)
return FALSE;
aes_set_decrypt_key (&aes_ctx.ctx, 16, key_data);
CBC_SET_IV (&aes_ctx, iv_data);
CBC_DECRYPT (&aes_ctx, aes_decrypt, length, decrypted_data, encrypted_data);
return TRUE;
}
#else
static gboolean
decrypt_fragment (GstHLSDemux * demux, gsize length,
const guint8 * encrypted_data, guint8 * decrypted_data,
const guint8 * key_data, const guint8 * iv_data)
{
gcry_cipher_hd_t aes_ctx = NULL;
gcry_error_t err = 0;
gboolean ret = FALSE;
err =
gcry_cipher_open (&aes_ctx, GCRY_CIPHER_AES128, GCRY_CIPHER_MODE_CBC, 0);
if (err)
goto out;
err = gcry_cipher_setkey (aes_ctx, key_data, 16);
if (err)
goto out;
err = gcry_cipher_setiv (aes_ctx, iv_data, 16);
if (err)
goto out;
err = gcry_cipher_decrypt (aes_ctx, decrypted_data, length,
encrypted_data, length);
if (err)
goto out;
ret = TRUE;
out:
if (aes_ctx)
gcry_cipher_close (aes_ctx);
return ret;
}
#endif
static GstFragment *
gst_hls_demux_decrypt_fragment (GstHLSDemux * demux,
GstFragment * encrypted_fragment, const gchar * key, const guint8 * iv,
GError ** err)
{
GstFragment *key_fragment, *ret = NULL;
GstBuffer *key_buffer, *encrypted_buffer, *decrypted_buffer;
GstMapInfo key_info, encrypted_info, decrypted_info;
gsize unpadded_size;
if (demux->key_url && strcmp (demux->key_url, key) == 0) {
key_fragment = g_object_ref (demux->key_fragment);
} else {
g_free (demux->key_url);
demux->key_url = NULL;
if (demux->key_fragment)
g_object_unref (demux->key_fragment);
demux->key_fragment = NULL;
GST_INFO_OBJECT (demux, "Fetching key %s", key);
key_fragment =
gst_uri_downloader_fetch_uri (demux->downloader, key, FALSE, err);
if (key_fragment == NULL)
goto key_failed;
demux->key_url = g_strdup (key);
demux->key_fragment = g_object_ref (key_fragment);
}
key_buffer = gst_fragment_get_buffer (key_fragment);
encrypted_buffer = gst_fragment_get_buffer (encrypted_fragment);
decrypted_buffer =
gst_buffer_new_allocate (NULL, gst_buffer_get_size (encrypted_buffer),
NULL);
gst_buffer_map (key_buffer, &key_info, GST_MAP_READ);
gst_buffer_map (encrypted_buffer, &encrypted_info, GST_MAP_READ);
gst_buffer_map (decrypted_buffer, &decrypted_info, GST_MAP_WRITE);
if (key_info.size != 16)
goto decrypt_error;
if (!decrypt_fragment (demux, encrypted_info.size,
encrypted_info.data, decrypted_info.data, key_info.data, iv))
goto decrypt_error;
/* Handle pkcs7 unpadding here */
unpadded_size =
decrypted_info.size - decrypted_info.data[decrypted_info.size - 1];
gst_buffer_unmap (decrypted_buffer, &decrypted_info);
gst_buffer_unmap (encrypted_buffer, &encrypted_info);
gst_buffer_unmap (key_buffer, &key_info);
gst_buffer_resize (decrypted_buffer, 0, unpadded_size);
gst_buffer_unref (key_buffer);
gst_buffer_unref (encrypted_buffer);
g_object_unref (key_fragment);
ret = gst_fragment_new ();
gst_fragment_add_buffer (ret, decrypted_buffer);
ret->completed = TRUE;
key_failed:
g_object_unref (encrypted_fragment);
return ret;
decrypt_error:
GST_ERROR_OBJECT (demux, "Failed to decrypt fragment");
g_set_error (err, GST_STREAM_ERROR, GST_STREAM_ERROR_DECRYPT,
"Failed to decrypt fragment");
gst_buffer_unmap (decrypted_buffer, &decrypted_info);
gst_buffer_unmap (encrypted_buffer, &encrypted_info);
gst_buffer_unmap (key_buffer, &key_info);
gst_buffer_unref (key_buffer);
gst_buffer_unref (encrypted_buffer);
gst_buffer_unref (decrypted_buffer);
g_object_unref (key_fragment);
g_object_unref (encrypted_fragment);
return ret;
}
static GstFragment *
gst_hls_demux_get_next_fragment (GstHLSDemux * demux,
gboolean * end_of_playlist, GError ** err)
{
GstFragment *download;
const gchar *next_fragment_uri;
GstClockTime duration;
GstClockTime timestamp;
GstBuffer *buf;
gboolean discont;
const gchar *key = NULL;
const guint8 *iv = NULL;
*end_of_playlist = FALSE;
if (!gst_m3u8_client_get_next_fragment (demux->client, &discont,
&next_fragment_uri, &duration, &timestamp, &key, &iv)) {
GST_INFO_OBJECT (demux, "This playlist doesn't contain more fragments");
*end_of_playlist = TRUE;
return NULL;
}
GST_INFO_OBJECT (demux, "Fetching next fragment %s", next_fragment_uri);
download = gst_uri_downloader_fetch_uri (demux->downloader,
next_fragment_uri, FALSE, err);
if (download == NULL)
goto error;
if (key) {
download = gst_hls_demux_decrypt_fragment (demux, download, key, iv, err);
if (download == NULL)
goto error;
}
buf = gst_fragment_get_buffer (download);
GST_DEBUG_OBJECT (demux, "set fragment pts=%" GST_TIME_FORMAT " duration=%"
GST_TIME_FORMAT, GST_TIME_ARGS (timestamp), GST_TIME_ARGS (duration));
GST_BUFFER_DURATION (buf) = duration;
GST_BUFFER_PTS (buf) = timestamp;
/* We actually need to do this every time we switch bitrate */
if (G_UNLIKELY (demux->do_typefind)) {
GstCaps *caps = gst_fragment_get_caps (download);
if (G_UNLIKELY (!caps)) {
GST_ELEMENT_ERROR (demux, STREAM, TYPE_NOT_FOUND,
("Could not determine type of stream"), (NULL));
gst_buffer_unref (buf);
g_object_unref (download);
goto error;
}
if (!demux->input_caps || !gst_caps_is_equal (caps, demux->input_caps)) {
gst_caps_replace (&demux->input_caps, caps);
/* gst_pad_set_caps (demux->srcpad, demux->input_caps); */
GST_INFO_OBJECT (demux, "Input source caps: %" GST_PTR_FORMAT,
demux->input_caps);
demux->do_typefind = FALSE;
}
gst_caps_unref (caps);
} else {
gst_fragment_set_caps (download, demux->input_caps);
}
if (discont) {
GST_DEBUG_OBJECT (demux, "Marking fragment as discontinuous");
GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
}
/* The buffer ref is still kept inside the fragment download */
gst_buffer_unref (buf);
return download;
error:
{
return NULL;
}
}
Reference in a new issue View git blame Copy permalink