Bug#1032972: handbrake: debian version of handbrake does not handle subtitles correctly
Hi Moritz On 29/01/2024 22:48, Moritz Mühlenhoff wrote: Can you please send/propose this upstream, they are in a much better position to assess this approach. Either by making a pull requesthttps://github.com/HandBrake/HandBrake or by opening an issue there. It has been reported here: https://github.com/HandBrake/HandBrake/issues/4029 In short: HandBrake developers insist that handbrake is buildt with their heavily patched version of ffmpeg (they prefer ffmpeg handling the pts). The Debian package gets branded as unsupported. FFmpeg on the other hand does not accept that "convenience" patch (reasoning "That makes no sense": https://trac.ffmpeg.org/ticket/10681). And Debian seems to be caught in the middle of the hardened positions between those two projects. So sorry, someone has already tried that, and unfortunately for human reasons that has failed. Debian has may sympathy, being the anonymous bystander caught in the proverbial crossfire. Thank you for your efforts to resolve this, Michael
Bug#1032972: handbrake: debian version of handbrake does not handle subtitles correctly
Hi Michael, thanks for looking into this! michael spreng wrote: > The above mentioned patch to ffmpeg changes ffmpeg to remember the pts. But > handbrake can remember the pts just as well. So see the attached patch which > does exactly that: if the subtitle is incomplete, it saves the pts to the > handbrake subtitle context, and retrieves it if there is no pts on a > completed subtitle ready for output. > > I am unsure how to proceed from here. Is that fix acceptable? Where would I > submit it? Can you please send/propose this upstream, they are in a much better position to assess this approach. Either by making a pull request https://github.com/HandBrake/HandBrake or by opening an issue there. Cheers, Moritz
Bug#1032972: handbrake: debian version of handbrake does not handle subtitles correctly
On Wed, 22 Nov 2023 16:04:21 +0100 michael spreng wrote: I stumbled on this issue as well. It looks to me like this patch: https://github.com/HandBrake/HandBrake/blob/master/contrib/ffmpeg/A07-dvdsubdec-use-pts-of-initial-packet.patch is particularly important for how handbrake handles dvd sub titles. My understanding is: dvd subtitles are large (being images) and will usually exceed a packet in the stream. ffmpeg only returns the pts with the first invocation (packet), where no complete subtitle results. The second invocation (packet), which usually completes the subtitle and results in a complete subtitle returned, does not contain the pts anymore. The above mentioned patch to ffmpeg changes ffmpeg to remember the pts. But handbrake can remember the pts just as well. So see the attached patch which does exactly that: if the subtitle is incomplete, it saves the pts to the handbrake subtitle context, and retrieves it if there is no pts on a completed subtitle ready for output. I am unsure how to proceed from here. Is that fix acceptable? Where would I submit it? I tried this patch out and it works. Subtitles are with right timings.
Bug#1032972: handbrake: debian version of handbrake does not handle subtitles correctly
I stumbled on this issue as well. It looks to me like this patch:
https://github.com/HandBrake/HandBrake/blob/master/contrib/ffmpeg/A07-dvdsubdec-use-pts-of-initial-packet.patch
is particularly important for how handbrake handles dvd sub titles.
My understanding is: dvd subtitles are large (being images) and will
usually exceed a packet in the stream. ffmpeg only returns the pts with
the first invocation (packet), where no complete subtitle results. The
second invocation (packet), which usually completes the subtitle and
results in a complete subtitle returned, does not contain the pts anymore.
The above mentioned patch to ffmpeg changes ffmpeg to remember the pts.
But handbrake can remember the pts just as well. So see the attached
patch which does exactly that: if the subtitle is incomplete, it saves
the pts to the handbrake subtitle context, and retrieves it if there is
no pts on a completed subtitle ready for output.
I am unsure how to proceed from here. Is that fix acceptable? Where
would I submit it?From: michael spreng
Date: Wed, 22 Nov 2023 15:36:17 +0100
Subject: [PATCH] Save pts of incomplete subtitle
Referring to bug "debian version of handbrake does NOT handle subtitles
correctly"
handbrake patches ffmpeg to save the pts of multi-packet subtitles
https://github.com/HandBrake/HandBrake/blob/master/contrib/ffmpeg/A07-dvdsubdec-use-pts-of-initial-packet.patch
As debian uses the system libraries, this patch implements the saving of
the pts in handbrake to fix subtitles for debian
---
libhb/decavsub.c | 19 ++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/libhb/decavsub.c b/libhb/decavsub.c
index aad32beb2..5738b1976 100644
--- a/libhb/decavsub.c
+++ b/libhb/decavsub.c
@@ -28,6 +28,12 @@ struct hb_avsub_context_s
// while this should really get fixed elsewhere,
// dropping subtitles should be avoided as much as possible
int64_t last_pts;
+// large subtitles (dvd sub, image based for example) can be split
+// across several packets. avcodec_decode_subtitle2 can return the
+// pts in a non complete packet (got_sub_ptr == 0). In that case
+// save the pts and reuse it once all packets were processed and
+// the subtitle is complete
+int64_t unused_pts;
// For PGS subs, we need to pass 'empty' subtitles through (they clear the
// display) - when doing forced-only extraction, only pass empty subtitles
// through if we've seen a forced sub since the last empty sub
@@ -49,6 +55,7 @@ hb_avsub_context_t * decavsubInit( hb_work_object_t * w, hb_job_t * job )
}
ctx->seen_forced_sub = 0;
ctx->last_pts = AV_NOPTS_VALUE;
+ctx->unused_pts= AV_NOPTS_VALUE;
ctx->job = job;
ctx->subtitle = w->subtitle;
@@ -360,6 +367,11 @@ int decavsubWork( hb_avsub_context_t * ctx,
if (!has_subtitle)
{
+if (subtitle.pts != AV_NOPTS_VALUE)
+{
+ctx->unused_pts = av_rescale(subtitle.pts, 9, AV_TIME_BASE) +
+ av_rescale(subtitle.start_display_time, 9, 1000);
+}
continue;
}
@@ -436,7 +448,11 @@ int decavsubWork( hb_avsub_context_t * ctx,
}
else
{
-if (in_s.start >= 0)
+if (ctx->unused_pts != AV_NOPTS_VALUE)
+{
+pts = ctx->unused_pts;
+}
+else if (in_s.start >= 0)
{
pts = in_s.start;
}
@@ -475,6 +491,7 @@ int decavsubWork( hb_avsub_context_t * ctx,
pts = ctx->last_pts + 1 * 9LL;
}
ctx->last_pts = pts;
+ctx->unused_pts = AV_NOPTS_VALUE;
if (ctx->subtitle->format == TEXTSUB)
{
--
2.39.2
Bug#1032972: handbrake: debian version of handbrake does NOT handle subtitles correctly
Package: handbrake-cli Version: 1.6.1+ds1-1 Ouch, yes, to confirm, upgraded to bookworm and now subtitles are broken when using HandBrake to convert DVD to .mkv (worked in bullseye handbrake-cli 1.3.1+ds1-2 and previous versions) The problem occurs with all DVD subs I tried, both types: VOBSUB and CC608 # Example command: HandBrakeCLI -i /dev/sr0 -o "7r0N.mkv" -t 1 -s 1 # Title 1, subtitle track 1 Produces lots of decavsub warnings (I'm guessing for every subtitle frame): [warning] decavsub: track 1, invalid PTS Result: video ok, but subtitles do not appear and/or not at the correct times. upstream: https://github.com/HandBrake/HandBrake/issues/4029 ...Handbrake depends on custom ffmpeg patches, hmmm...?
Bug#1032972: handbrake: debian version of handbrake does NOT handle subtitles correctly
This is the exact version of handbrake I used from fr.handbrake.ghb that fixed the subtitles issue (which seems caused because the character encoding of the subtitles is not always recognized): => flatpak info fr.handbrake.ghb HandBrake - Video Transcoder ID: fr.handbrake.ghb Ref: app/fr.handbrake.ghb/x86_64/stable Arch: x86_64 Branch: stable Version: 1.6.1 License: GPL-2.0+ Origin: ghb-origin Collection: Installation: user Installed: 123.3 MB Runtime: org.gnome.Platform/x86_64/43 Sdk: org.gnome.Sdk/x86_64/43 Commit: 227d2a8398a850cd93a6662116c0bc64be187eeb4f2e5a2ae1e490838cd03248 Subject: Export fr.handbrake.ghb Date: 2023-01-23 18:08:28 +
Bug#1032972: handbrake: debian version of handbrake does NOT handle subtitles correctly
I've installed the snapshot version of handbrake from handbrake.fr directly (via flatpak)and verified that on the same DVDs, it generates the subtitles perfectly. I also built the debian version of handbrake from source and that one still has the same problems.One can also see the subtitles overlaying each other so that in rapid dialog multiple subtitles appearone on top of each other, making them all illegible. This does not happen in the handbrake snaphshot. thanks,--jack
Bug#1032972: handbrake: debian version of handbrake does NOT handle subtitles correctly
Package: handbrake Version: 1.6.1+ds1-1 Severity: important Dear Maintainer, === * What led up to the situation? Tried to convert 2 different DVDs, both NTSC, into m4v (or mp4) including subtitles. In both cases, using many different options for handbrake (H264, H265, different audio encoders, etc), was easily able add subtitles (as well as burn-in). HOWEVER: the subtitles NEVER worked correctly: - there are places where characters speak and no subtitles appear at all - also places where characters speak at length and a subtitle pops up for only a second - parts where there is lenghty narration, but no character speaks, and no subtitle appears ever NOTE: in both DVDs, playing the DVD directly results in subtitles working perfectly. The DVDs have subtitles working but the debian package of handbrake does not work. * What exactly did you do (or not do) that was effective (or ineffective)? I contacted handbrake.fr and they recommended using their nightly snapshot as they claim debian is using a version of ffmpeg that breaks subtitles. Entire thread is at: https://forum.handbrake.fr/viewtopic.php?p=202972#p202972 Using the nightly snapshot from handbrake.fr worked perfectly and produced an m4v file with subtitles that match exactly the characters. * What outcome did you expect instead? I expected the debian packaged handbrake to work exactly as the one from the upstream source but it does not. Failure to generate all subtitles and insert them at the correct spot in the video is a major failure that makes this packaged version of handbrake unusable for videos with subtitles. I recommend adding a test case of ripping a DVD with subtitles AND verifying that the subtitles really match the speech. === -- System Information: Debian Release: bookworm/sid APT prefers testing-security APT policy: (500, 'testing-security'), (500, 'testing') Architecture: amd64 (x86_64) Kernel: Linux 6.1.0-1-amd64 (SMP w/6 CPU threads; PREEMPT) Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_FIRMWARE_WORKAROUND, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to C.UTF-8), LANGUAGE not set Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) Versions of packages handbrake depends on: ii libass91:0.17.0-2 ii libavcodec-extra59 [libavcodec59] 7:5.1.2-3 ii libavfilter-extra8 [libavfilter8] 7:5.1.2-3 ii libavformat59 7:5.1.2-3 ii libavutil577:5.1.2-3 ii libbluray2 1:1.3.4-1 ii libc6 2.36-8 ii libcairo2 1.16.0-7 ii libdvdnav4 6.1.1-1 ii libdvdread86.1.3-1 ii libgdk-pixbuf-2.0-02.42.10+dfsg-1+b1 ii libglib2.0-0 2.74.5-1 ii libgstreamer-plugins-base1.0-0 1.22.0-3 ii libgstreamer1.0-0 1.22.0-2 ii libgtk-3-0 3.24.36-4 ii libgudev-1.0-0 237-2 ii libjansson42.14-2 ii libpango-1.0-0 1.50.12+ds-1 ii libswresample4 7:5.1.2-3 ii libswscale67:5.1.2-3 ii libtheora0 1.1.1+dfsg.1-16.1 ii libturbojpeg0 1:2.1.5-2 ii libva-drm2 2.17.0-1 ii libva2 2.17.0-1 ii libvorbis0a1.3.7-1 ii libvorbisenc2 1.3.7-1 ii libvpl22023.1.1-1 ii libx264-1642:0.164.3095+gitbaee400-2+b1 ii libx265-1993.5-2+b1 ii libxml22.9.14+dfsg-1.1+b3 Versions of packages handbrake recommends: ii gstreamer1.0-alsa1.22.0-3 ii gstreamer1.0-libav 1.22.0-2 ii gstreamer1.0-pulseaudio 1.22.0-4 ii gstreamer1.0-x 1.22.0-3 handbrake suggests no packages. -- no debconf information
