Re: [FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-02-02 Thread Bodecs Bela 



2017.02.03. 0:27 keltezéssel, Aman Gupta írta:

On Wed, Feb 1, 2017 at 6:03 AM, Bodecs Bela  wrote:



2017.01.31. 21:29 keltezéssel, Aman Gupta írta:


From: Aman Gupta 

Adds a `-hls_flags +temp_file` which will write segment data to
filename.tmp, and then rename to filename when the segment is complete
and before the file is added to the m3u8 playlist.

This patch is similar in spirit to one used in Plex's ffmpeg fork, and
allows a transcoding webserver to ensure incomplete segment files are
never served up accidentally.
---
   libavformat/hlsenc.c | 15 +++
   1 file changed, 15 insertions(+)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index bd1e684..23b9011 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -76,6 +76,7 @@ typedef enum HLSFlags {
   HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index
in segment filenames when use_localtime  e.g.: %%03d
   HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment
duration (microsec) in segment filenames when use_localtime  e.g.: %%09t
   HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size
(bytes) in segment filenames when use_localtime  e.g.: %%014s
+HLS_TEMP_FILE = (1 << 11),
   } HLSFlags;
 typedef enum {
@@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
 set_http_options(, c);
   +if (c->flags & HLS_TEMP_FILE) {
+av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
+}
+
   if (c->key_info_file) {
   if ((err = hls_encryption_start(s)) < 0)
   goto fail;
@@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s,
AVPacket *pkt)
 av_write_frame(oc, NULL); /* Flush any buffered data */
   +if (hls->flags & HLS_TEMP_FILE) {
+size_t len = strlen(oc->filename);
+char final_filename[sizeof(oc->filename)];
+av_strlcpy(final_filename, oc->filename, len);
+final_filename[len-4] = '\0';
+ff_rename(oc->filename, final_filename, s);
+oc->filename[len-4] = '\0';
+}
+
   new_start_pos = avio_tell(hls->avf->pb);
   hls->size = new_start_pos - hls->start_pos;
   ret = hls_append_segment(s, hls, hls->duration, hls->start_pos,
hls->size);
@@ -1406,6 +1420,7 @@ static const AVOption options[] = {
   {"hls_subtitle_path", "set path of hls subtitles",
OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
   {"hls_flags", "set flags affecting HLS playlist and media file
generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E,
"flags"},
   {"single_file",   "generate a single media file indexed with byte
ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E,
"flags"},
+{"temp_file", "write segment to temporary file and rename when
complete", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E,
"flags"},
   {"delete_segments", "delete segment files that are no longer part
of the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0,
UINT_MAX,   E, "flags"},
   {"round_durations", "round durations in m3u8 to whole numbers", 0,
AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E,
"flags"},
   {"discont_start", "start the playlist with a discontinuity tag", 0,
AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},


I think the phrase  in your email subject "to create atomically"
misleading because another renaming may occur afterwards your temp renaming
if second_level_segment_size or second_level_segment_duration flag is on.
But the idea to write segment content into a temp file is good by me. To
ensure the amoticity the two distinct renamings may be merged.


I agree my use of "atomic" is confusing. I removed this from the commit
message in v2 of the patch.



I have never thought of it but after your idea I concluded  that the
segment file names are predictable.
In live streaming enviroment somebody predicting the segment name may see
the program some seconds earlier than any other viewer by downloading the
unpublished segment. (with one segment duration seconds earlier)
If the temp file name would be random name, then your idea may be seen as
a security feature.
What is your opinion about this possibility?


I don't have a strong opinion on this. Presumably if someone is concerned
about this, they can still use my temp_file patch and configure their web
server to reject any requests for *.tmp

Yes, I agree with you. Maybe You can put a short notice about this into 
the documentation.


bb

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Re: [FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-02-02 Thread Aman Gupta 
On Wed, Feb 1, 2017 at 6:03 AM, Bodecs Bela  wrote:

>
>
> 2017.01.31. 21:29 keltezéssel, Aman Gupta írta:
>
>> From: Aman Gupta 
>>
>> Adds a `-hls_flags +temp_file` which will write segment data to
>> filename.tmp, and then rename to filename when the segment is complete
>> and before the file is added to the m3u8 playlist.
>>
>> This patch is similar in spirit to one used in Plex's ffmpeg fork, and
>> allows a transcoding webserver to ensure incomplete segment files are
>> never served up accidentally.
>> ---
>>   libavformat/hlsenc.c | 15 +++
>>   1 file changed, 15 insertions(+)
>>
>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>> index bd1e684..23b9011 100644
>> --- a/libavformat/hlsenc.c
>> +++ b/libavformat/hlsenc.c
>> @@ -76,6 +76,7 @@ typedef enum HLSFlags {
>>   HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index
>> in segment filenames when use_localtime  e.g.: %%03d
>>   HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment
>> duration (microsec) in segment filenames when use_localtime  e.g.: %%09t
>>   HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size
>> (bytes) in segment filenames when use_localtime  e.g.: %%014s
>> +HLS_TEMP_FILE = (1 << 11),
>>   } HLSFlags;
>> typedef enum {
>> @@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
>> set_http_options(, c);
>>   +if (c->flags & HLS_TEMP_FILE) {
>> +av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
>> +}
>> +
>>   if (c->key_info_file) {
>>   if ((err = hls_encryption_start(s)) < 0)
>>   goto fail;
>> @@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>> av_write_frame(oc, NULL); /* Flush any buffered data */
>>   +if (hls->flags & HLS_TEMP_FILE) {
>> +size_t len = strlen(oc->filename);
>> +char final_filename[sizeof(oc->filename)];
>> +av_strlcpy(final_filename, oc->filename, len);
>> +final_filename[len-4] = '\0';
>> +ff_rename(oc->filename, final_filename, s);
>> +oc->filename[len-4] = '\0';
>> +}
>> +
>>   new_start_pos = avio_tell(hls->avf->pb);
>>   hls->size = new_start_pos - hls->start_pos;
>>   ret = hls_append_segment(s, hls, hls->duration, hls->start_pos,
>> hls->size);
>> @@ -1406,6 +1420,7 @@ static const AVOption options[] = {
>>   {"hls_subtitle_path", "set path of hls subtitles",
>> OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
>>   {"hls_flags", "set flags affecting HLS playlist and media file
>> generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E,
>> "flags"},
>>   {"single_file",   "generate a single media file indexed with byte
>> ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E,
>> "flags"},
>> +{"temp_file", "write segment to temporary file and rename when
>> complete", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E,
>> "flags"},
>>   {"delete_segments", "delete segment files that are no longer part
>> of the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0,
>> UINT_MAX,   E, "flags"},
>>   {"round_durations", "round durations in m3u8 to whole numbers", 0,
>> AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E,
>> "flags"},
>>   {"discont_start", "start the playlist with a discontinuity tag", 0,
>> AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},
>>
> I think the phrase  in your email subject "to create atomically"
> misleading because another renaming may occur afterwards your temp renaming
> if second_level_segment_size or second_level_segment_duration flag is on.
> But the idea to write segment content into a temp file is good by me. To
> ensure the amoticity the two distinct renamings may be merged.
>

I agree my use of "atomic" is confusing. I removed this from the commit
message in v2 of the patch.


>
> I have never thought of it but after your idea I concluded  that the
> segment file names are predictable.
> In live streaming enviroment somebody predicting the segment name may see
> the program some seconds earlier than any other viewer by downloading the
> unpublished segment. (with one segment duration seconds earlier)
> If the temp file name would be random name, then your idea may be seen as
> a security feature.
> What is your opinion about this possibility?


I don't have a strong opinion on this. Presumably if someone is concerned
about this, they can still use my temp_file patch and configure their web
server to reject any requests for *.tmp


>
>
> bb
>
> ___
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> ffmpeg-devel@ffmpeg.org
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Re: [FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-02-01 Thread Aman Gupta 
On Tue, Jan 31, 2017 at 12:29 PM, Aman Gupta  wrote:

> From: Aman Gupta 
>
> Adds a `-hls_flags +temp_file` which will write segment data to
> filename.tmp, and then rename to filename when the segment is complete
> and before the file is added to the m3u8 playlist.
>
> This patch is similar in spirit to one used in Plex's ffmpeg fork, and
> allows a transcoding webserver to ensure incomplete segment files are
> never served up accidentally.
> ---
>  libavformat/hlsenc.c | 15 +++
>  1 file changed, 15 insertions(+)
>
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index bd1e684..23b9011 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -76,6 +76,7 @@ typedef enum HLSFlags {
>  HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index
> in segment filenames when use_localtime  e.g.: %%03d
>  HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment
> duration (microsec) in segment filenames when use_localtime  e.g.: %%09t
>  HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size
> (bytes) in segment filenames when use_localtime  e.g.: %%014s
> +HLS_TEMP_FILE = (1 << 11),
>  } HLSFlags;
>
>  typedef enum {
> @@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
>
>  set_http_options(, c);
>
> +if (c->flags & HLS_TEMP_FILE) {
> +av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
> +}
> +
>  if (c->key_info_file) {
>  if ((err = hls_encryption_start(s)) < 0)
>  goto fail;
> @@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>
>  av_write_frame(oc, NULL); /* Flush any buffered data */
>
> +if (hls->flags & HLS_TEMP_FILE) {
> +size_t len = strlen(oc->filename);
> +char final_filename[sizeof(oc->filename)];
> +av_strlcpy(final_filename, oc->filename, len);
> +final_filename[len-4] = '\0';
> +ff_rename(oc->filename, final_filename, s);
>

This doesn't work on windows, since you cannot rename the file while it is
still open. Strangely ff_rename is not logging any errors in this case.


> +oc->filename[len-4] = '\0';
> +}
> +
>  new_start_pos = avio_tell(hls->avf->pb);
>  hls->size = new_start_pos - hls->start_pos;
>  ret = hls_append_segment(s, hls, hls->duration, hls->start_pos,
> hls->size);
> @@ -1406,6 +1420,7 @@ static const AVOption options[] = {
>  {"hls_subtitle_path", "set path of hls subtitles",
> OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
>  {"hls_flags", "set flags affecting HLS playlist and media file
> generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E,
> "flags"},
>  {"single_file",   "generate a single media file indexed with byte
> ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E,
> "flags"},
> +{"temp_file", "write segment to temporary file and rename when
> complete", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E,
> "flags"},
>  {"delete_segments", "delete segment files that are no longer part of
> the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0,
> UINT_MAX,   E, "flags"},
>  {"round_durations", "round durations in m3u8 to whole numbers", 0,
> AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E,
> "flags"},
>  {"discont_start", "start the playlist with a discontinuity tag", 0,
> AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},
> --
> 2.10.1 (Apple Git-78)
>
>
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Re: [FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-02-01 Thread Bodecs Bela 



2017.01.31. 21:29 keltezéssel, Aman Gupta írta:

From: Aman Gupta 

Adds a `-hls_flags +temp_file` which will write segment data to
filename.tmp, and then rename to filename when the segment is complete
and before the file is added to the m3u8 playlist.

This patch is similar in spirit to one used in Plex's ffmpeg fork, and
allows a transcoding webserver to ensure incomplete segment files are
never served up accidentally.
---
  libavformat/hlsenc.c | 15 +++
  1 file changed, 15 insertions(+)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index bd1e684..23b9011 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -76,6 +76,7 @@ typedef enum HLSFlags {
  HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index in 
segment filenames when use_localtime  e.g.: %%03d
  HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment duration 
(microsec) in segment filenames when use_localtime  e.g.: %%09t
  HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size 
(bytes) in segment filenames when use_localtime  e.g.: %%014s
+HLS_TEMP_FILE = (1 << 11),
  } HLSFlags;
  
  typedef enum {

@@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
  
  set_http_options(, c);
  
+if (c->flags & HLS_TEMP_FILE) {

+av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
+}
+
  if (c->key_info_file) {
  if ((err = hls_encryption_start(s)) < 0)
  goto fail;
@@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s, AVPacket 
*pkt)
  
  av_write_frame(oc, NULL); /* Flush any buffered data */
  
+if (hls->flags & HLS_TEMP_FILE) {

+size_t len = strlen(oc->filename);
+char final_filename[sizeof(oc->filename)];
+av_strlcpy(final_filename, oc->filename, len);
+final_filename[len-4] = '\0';
+ff_rename(oc->filename, final_filename, s);
+oc->filename[len-4] = '\0';
+}
+
  new_start_pos = avio_tell(hls->avf->pb);
  hls->size = new_start_pos - hls->start_pos;
  ret = hls_append_segment(s, hls, hls->duration, hls->start_pos, 
hls->size);
@@ -1406,6 +1420,7 @@ static const AVOption options[] = {
  {"hls_subtitle_path", "set path of hls subtitles", 
OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
  {"hls_flags", "set flags affecting HLS playlist and media file generation", 
OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E, "flags"},
  {"single_file",   "generate a single media file indexed with byte ranges", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E, "flags"},
+{"temp_file", "write segment to temporary file and rename when complete", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E, "flags"},
  {"delete_segments", "delete segment files that are no longer part of the playlist", 
0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0, UINT_MAX,   E, "flags"},
  {"round_durations", "round durations in m3u8 to whole numbers", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E, "flags"},
  {"discont_start", "start the playlist with a discontinuity tag", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},
I think the phrase  in your email subject "to create atomically" 
misleading because another renaming may occur afterwards your temp 
renaming if second_level_segment_size or second_level_segment_duration 
flag is on.
But the idea to write segment content into a temp file is good by me. To 
ensure the amoticity the two distinct renamings may be merged.


I have never thought of it but after your idea I concluded  that the 
segment file names are predictable.
In live streaming enviroment somebody predicting the segment name may 
see the program some seconds earlier than any other viewer by 
downloading the unpublished segment. (with one segment duration seconds 
earlier)
If the temp file name would be random name, then your idea may be seen 
as a security feature.

What is your opinion about this possibility?

bb
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Re: [FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-02-01 Thread Steven Liu 
2017-02-01 4:29 GMT+08:00 Aman Gupta :

> From: Aman Gupta 
>
> Adds a `-hls_flags +temp_file` which will write segment data to
> filename.tmp, and then rename to filename when the segment is complete
> and before the file is added to the m3u8 playlist.
>
> This patch is similar in spirit to one used in Plex's ffmpeg fork, and
> allows a transcoding webserver to ensure incomplete segment files are
> never served up accidentally.
> ---
>  libavformat/hlsenc.c | 15 +++
>  1 file changed, 15 insertions(+)
>
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index bd1e684..23b9011 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -76,6 +76,7 @@ typedef enum HLSFlags {
>  HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index
> in segment filenames when use_localtime  e.g.: %%03d
>  HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment
> duration (microsec) in segment filenames when use_localtime  e.g.: %%09t
>  HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size
> (bytes) in segment filenames when use_localtime  e.g.: %%014s
> +HLS_TEMP_FILE = (1 << 11),
>  } HLSFlags;
>
>  typedef enum {
> @@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
>
>  set_http_options(, c);
>
> +if (c->flags & HLS_TEMP_FILE) {
> +av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
> +}
> +
>  if (c->key_info_file) {
>  if ((err = hls_encryption_start(s)) < 0)
>  goto fail;
> @@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s,
> AVPacket *pkt)
>
>  av_write_frame(oc, NULL); /* Flush any buffered data */
>
> +if (hls->flags & HLS_TEMP_FILE) {
> +size_t len = strlen(oc->filename);
> +char final_filename[sizeof(oc->filename)];
> +av_strlcpy(final_filename, oc->filename, len);
> +final_filename[len-4] = '\0';
> +ff_rename(oc->filename, final_filename, s);
> +oc->filename[len-4] = '\0';
> +}
> +
>  new_start_pos = avio_tell(hls->avf->pb);
>  hls->size = new_start_pos - hls->start_pos;
>  ret = hls_append_segment(s, hls, hls->duration, hls->start_pos,
> hls->size);
> @@ -1406,6 +1420,7 @@ static const AVOption options[] = {
>  {"hls_subtitle_path", "set path of hls subtitles",
> OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
>  {"hls_flags", "set flags affecting HLS playlist and media file
> generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E,
> "flags"},
>  {"single_file",   "generate a single media file indexed with byte
> ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E,
> "flags"},
> +{"temp_file", "write segment to temporary file and rename when
> complete", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E,
> "flags"},
>  {"delete_segments", "delete segment files that are no longer part of
> the playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0,
> UINT_MAX,   E, "flags"},
>  {"round_durations", "round durations in m3u8 to whole numbers", 0,
> AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E,
> "flags"},
>  {"discont_start", "start the playlist with a discontinuity tag", 0,
> AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},
> --
> 2.10.1 (Apple Git-78)
>
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>


Why use temp filename?
There have no info in m3u8 list before the segment complete.
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[FFmpeg-devel] [PATCH] avformat/hlsenc: add hls_flag option to create segments atomically

2017-01-31 Thread Aman Gupta 
From: Aman Gupta 

Adds a `-hls_flags +temp_file` which will write segment data to
filename.tmp, and then rename to filename when the segment is complete
and before the file is added to the m3u8 playlist.

This patch is similar in spirit to one used in Plex's ffmpeg fork, and
allows a transcoding webserver to ensure incomplete segment files are
never served up accidentally.
---
 libavformat/hlsenc.c | 15 +++
 1 file changed, 15 insertions(+)

diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index bd1e684..23b9011 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -76,6 +76,7 @@ typedef enum HLSFlags {
 HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), // include segment index in 
segment filenames when use_localtime  e.g.: %%03d
 HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), // include segment duration 
(microsec) in segment filenames when use_localtime  e.g.: %%09t
 HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), // include segment size (bytes) 
in segment filenames when use_localtime  e.g.: %%014s
+HLS_TEMP_FILE = (1 << 11),
 } HLSFlags;
 
 typedef enum {
@@ -915,6 +916,10 @@ static int hls_start(AVFormatContext *s)
 
 set_http_options(, c);
 
+if (c->flags & HLS_TEMP_FILE) {
+av_strlcat(oc->filename, ".tmp", sizeof(oc->filename));
+}
+
 if (c->key_info_file) {
 if ((err = hls_encryption_start(s)) < 0)
 goto fail;
@@ -1276,6 +1281,15 @@ static int hls_write_packet(AVFormatContext *s, AVPacket 
*pkt)
 
 av_write_frame(oc, NULL); /* Flush any buffered data */
 
+if (hls->flags & HLS_TEMP_FILE) {
+size_t len = strlen(oc->filename);
+char final_filename[sizeof(oc->filename)];
+av_strlcpy(final_filename, oc->filename, len);
+final_filename[len-4] = '\0';
+ff_rename(oc->filename, final_filename, s);
+oc->filename[len-4] = '\0';
+}
+
 new_start_pos = avio_tell(hls->avf->pb);
 hls->size = new_start_pos - hls->start_pos;
 ret = hls_append_segment(s, hls, hls->duration, hls->start_pos, 
hls->size);
@@ -1406,6 +1420,7 @@ static const AVOption options[] = {
 {"hls_subtitle_path", "set path of hls subtitles", 
OFFSET(subtitle_filename), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,E},
 {"hls_flags", "set flags affecting HLS playlist and media file 
generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E, 
"flags"},
 {"single_file",   "generate a single media file indexed with byte ranges", 
0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E, "flags"},
+{"temp_file", "write segment to temporary file and rename when complete", 
0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E, "flags"},
 {"delete_segments", "delete segment files that are no longer part of the 
playlist", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_DELETE_SEGMENTS }, 0, UINT_MAX,   
E, "flags"},
 {"round_durations", "round durations in m3u8 to whole numbers", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_ROUND_DURATIONS }, 0, UINT_MAX,   E, "flags"},
 {"discont_start", "start the playlist with a discontinuity tag", 0, 
AV_OPT_TYPE_CONST, {.i64 = HLS_DISCONT_START }, 0, UINT_MAX,   E, "flags"},
-- 
2.10.1 (Apple Git-78)

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