Re: [FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
On Fri, 12 Jun 2015 00:11:24 +0530 Niklesh Lalwani niklesh.lalw...@iitb.ac.in wrote: Ok so it goes like this. We first find out the height and width of the video stream from the header box. The dimensions of the text track (subtitle track) is then set (in pixels). Here, we have used the width equal to the width of the video, and height equal to 1/10 of the video height. The write matrix specifies the coordinate origin and the translation values from the origin, ie, where to place the subtitle track. Here, we have set tx = 0; and ty = 9/10 of the video track height. There is also a text box inside this subtitle area, inside which the text is rendered. For now, this is set equal to the the subtitle track dimensions. Philip, please correct me if I am wrong. Nicolas was asking about the general mechanism, I think. So, the subtitle track has dimensions, just like the video track, and for a given set of dimensions, it can be placed at a position within the video track's dimensions. In Nikleh's example, it's the same width, and 1/10 of the height, and placed 9/10'th down, so as to occupy the bottom 1/10 of the display area. Within the subtitle area, specific subtitles occupy text boxes that can be smaller than the full area. In our simple example, all subtitles are in the same box that occupies the full area. --phil ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
Le tridi 23 prairial, an CCXXIII, Niklesh Lalwani a écrit : From: Niklesh niklesh.lalw...@iitb.ac.in This patch mostly replicates the concept patch posted by Philip https://ffmpeg.org/pipermail/ffmpeg-devel/2013-March/140299.html. This sets the proper dimensions for the subtitle tracks, by making use of the height and width of the video stream. The patch is exlained in detail in the link. Signed-off-by: Niklesh niklesh.lalw...@iitb.ac.in --- libavformat/movenc.c | 38 ++ libavformat/movenc.h | 4 2 files changed, 38 insertions(+), 4 deletions(-) I said it in the original thread and I say it again now: this is not the proper place, it should happen in the encoder and the surrounding applications. Regards, -- Nicolas George signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
On 2015-06-11 00:42, Nicolas George wrote: Le tridi 23 prairial, an CCXXIII, Niklesh Lalwani a écrit : From: Niklesh niklesh.lalw...@iitb.ac.in This patch mostly replicates the concept patch posted by Philip https://ffmpeg.org/pipermail/ffmpeg-devel/2013-March/140299.html. This sets the proper dimensions for the subtitle tracks, by making use of the height and width of the video stream. The patch is exlained in detail in the link. Signed-off-by: Niklesh niklesh.lalw...@iitb.ac.in --- libavformat/movenc.c | 38 ++ libavformat/movenc.h | 4 2 files changed, 38 insertions(+), 4 deletions(-) I said it in the original thread and I say it again now: this is not the proper place, it should happen in the encoder and the surrounding applications. Yeah. I sent this to Niklesh to unblock his other work, but we need a proper approach to setting the dimensions and this isn't it. --phil ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
Le tridi 23 prairial, an CCXXIII, Philip Langdale a écrit : Yeah. I sent this to Niklesh to unblock his other work, but we need a proper approach to setting the dimensions and this isn't it. Can you (or Niklesh) describe exactly the factors that guide the geometry of the text on screen? IIRC, in the original thread, there was mention of a matrix on top of the video resolution. Regards, -- Nicolas George signature.asc Description: Digital signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Re: [FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
Ok so it goes like this. We first find out the height and width of the video stream from the header box. The dimensions of the text track (subtitle track) is then set (in pixels). Here, we have used the width equal to the width of the video, and height equal to 1/10 of the video height. The write matrix specifies the coordinate origin and the translation values from the origin, ie, where to place the subtitle track. Here, we have set tx = 0; and ty = 9/10 of the video track height. There is also a text box inside this subtitle area, inside which the text is rendered. For now, this is set equal to the the subtitle track dimensions. Philip, please correct me if I am wrong. Thanks, Niklesh On Thu, Jun 11, 2015 at 11:09 PM, Nicolas George geo...@nsup.org wrote: Le tridi 23 prairial, an CCXXIII, Philip Langdale a écrit : Yeah. I sent this to Niklesh to unblock his other work, but we need a proper approach to setting the dimensions and this isn't it. Can you (or Niklesh) describe exactly the factors that guide the geometry of the text on screen? IIRC, in the original thread, there was mention of a matrix on top of the video resolution. Regards, -- Nicolas George ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
[FFmpeg-devel] [PATCH 1/2] Set subtitle track dimensions for mov_text to display the subtitles properly
From: Niklesh niklesh.lalw...@iitb.ac.in
This patch mostly replicates the concept patch posted by Philip
https://ffmpeg.org/pipermail/ffmpeg-devel/2013-March/140299.html. This sets the
proper dimensions for the subtitle tracks, by making use of the height and
width of the video stream. The patch is exlained in detail in the link.
Signed-off-by: Niklesh niklesh.lalw...@iitb.ac.in
---
libavformat/movenc.c | 38 ++
libavformat/movenc.h | 4
2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index dc9570b..c55219e 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1505,8 +1505,20 @@ static int mov_write_subtitle_tag(AVIOContext *pb,
MOVTrack *track)
if (track-enc-codec_id == AV_CODEC_ID_DVD_SUBTITLE)
mov_write_esds_tag(pb, track);
-else if (track-enc-extradata_size)
+else if (track-enc-extradata_size) {
+if (track-enc-extradata_size = 18) {
+// Rewrite text box dimensions to match video stream.
+uint8_t *ed = track-enc-extradata;
+uint16_t width = track-video_width;
+uint16_t height = track-video_height;
+height /= 10;
+ed[14] = height 8;
+ed[15] = height 0xFF;
+ed[16] = width 8;
+ed[17] = width 0xFF;
+ }
avio_write(pb, track-enc-extradata, track-enc-extradata_size);
+}
return update_size(pb, pos);
}
@@ -2335,7 +2347,7 @@ static int mov_write_tkhd_tag(AVIOContext *pb,
MOVMuxContext *mov,
avio_wb32(pb, 0); /* reserved */
avio_wb32(pb, 0); /* reserved */
-avio_wb16(pb, 0); /* layer */
+avio_wb16(pb, -1); /* layer */
avio_wb16(pb, group); /* alternate group) */
/* Volume, only for audio */
if (track-enc-codec_type == AVMEDIA_TYPE_AUDIO)
@@ -2352,6 +2364,8 @@ static int mov_write_tkhd_tag(AVIOContext *pb,
MOVMuxContext *mov,
if (display_matrix) {
for (i = 0; i 9; i++)
avio_wb32(pb, display_matrix[i]);
+} else if (track-enc-codec_type == AVMEDIA_TYPE_SUBTITLE) {
+write_matrix(pb, 1, 0, 0, 1, 0, (track-video_height*9)/10);
} else if (rotation == 90) {
write_matrix(pb, 0, 1, -1, 0, track-enc-height, 0);
} else if (rotation == 180) {
@@ -2362,8 +2376,7 @@ static int mov_write_tkhd_tag(AVIOContext *pb,
MOVMuxContext *mov,
write_matrix(pb, 1, 0, 0, 1, 0, 0);
}
/* Track width and height, for visual only */
-if (st (track-enc-codec_type == AVMEDIA_TYPE_VIDEO ||
- track-enc-codec_type == AVMEDIA_TYPE_SUBTITLE)) {
+if (st (track-enc-codec_type == AVMEDIA_TYPE_VIDEO)) {
if (track-mode == MODE_MOV) {
avio_wb32(pb, track-enc-width 16);
avio_wb32(pb, track-height 16);
@@ -2374,6 +2387,9 @@ static int mov_write_tkhd_tag(AVIOContext *pb,
MOVMuxContext *mov,
avio_wb32(pb, sample_aspect_ratio * track-enc-width * 0x1);
avio_wb32(pb, track-height * 0x1);
}
+} else if (st track-enc-codec_type == AVMEDIA_TYPE_SUBTITLE) {
+avio_wb32(pb, track-video_width * 0x1);
+avio_wb32(pb, (track-video_height * 0x1) / 10);
} else {
avio_wb32(pb, 0);
avio_wb32(pb, 0);
@@ -5216,6 +5232,20 @@ static int mov_write_header(AVFormatContext *s)
}
}
+for (i = 0; i mov-nb_streams; i++) {
+MOVTrack *track = mov-tracks[i];
+if (track-enc-codec_type == AVMEDIA_TYPE_SUBTITLE) {
+int j;
+for (j = 0; j mov-nb_streams; j++) {
+if (mov-tracks[j].enc-codec_type == AVMEDIA_TYPE_VIDEO) {
+track-video_width = mov-tracks[j].enc-width;
+track-video_height = mov-tracks[j].enc-height;
+break;
+}
+}
+}
+}
+
enable_tracks(s);
diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index 744d14e..c89a59e 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -148,6 +148,10 @@ typedef struct MOVTrack {
int slices;
} vc1_info;
+// For subtitle tracks.
+uint16_t video_width;
+uint16_t video_height;
+
void *eac3_priv;
} MOVTrack;
--
1.9.1
___
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
