[FFmpeg-devel] [PATCH] avformat/subfile: allow to extract till EOF

[Gyan Doshi]

Attached patch allows users to set end offset as 0 to extract till end 
of file.

Tested locally and documented.

Regards,
Gyan
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From e5c555774f88639f0e9337f1b55733d0ad156b64 Mon Sep 17 00:00:00 2001
From: Gyan Doshi <gyandoshi at gmail.com>
Date: Wed, 15 Nov 2017 17:12:30 +0530
Subject: [PATCH] avformat/subfile: allow to extract till EOF

Users can set end offset as 0 to extract till end of file.
Tested locally and documented.
---
 doc/protocols.texi    | 8 +++++++-
 libavformat/subfile.c | 3 +++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/doc/protocols.texi b/doc/protocols.texi
index a7968ff56e..18c72532e1 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -1186,6 +1186,7 @@ Accepted options:
 Start offset of the extracted segment, in bytes.
 @item end
 End offset of the extracted segment, in bytes.
+If set to 0, extract till end of file.
 @end table
 
 Examples:
@@ -1193,7 +1194,7 @@ Examples:
 Extract a chapter from a DVD VOB file (start and end sectors obtained
 externally and multiplied by 2048):
 @example
-subfile,,start,153391104,end,268142592,,:/media/dvd/VIDEO_TS/VTS_08_1.VOB
+ffmpeg subfile,,start,153391104,end,268142592,,:/media/dvd/VIDEO_TS/VTS_08_1.VOB
 @end example
 
 Play an AVI file directly from a TAR archive:
@@ -1201,6 +1202,11 @@ Play an AVI file directly from a TAR archive:
 subfile,,start,183241728,end,366490624,,:archive.tar
 @end example
 
+Play a MPEG-TS file from start offset till end:
+ at example
+subfile,,start,32815239,end,0,,:video.ts
+ at end example
+
 @section tee
 
 Writes the output to multiple protocols. The individual outputs are separated
diff --git a/libavformat/subfile.c b/libavformat/subfile.c
index 497cf85211..2094cdcdd0 100644
--- a/libavformat/subfile.c
+++ b/libavformat/subfile.c
@@ -72,6 +72,9 @@ static int subfile_open(URLContext *h, const char *filename, int flags,
     SubfileContext *c = h->priv_data;
     int ret;
 
+    if (c->end == 0)
+        c->end = INT64_MAX;
+
     if (c->end <= c->start) {
         av_log(h, AV_LOG_ERROR, "end before start\n");
         return AVERROR(EINVAL);
-- 
2.11.1.windows.1