avformat/matroskaenc: Don't waste bytes in EBML Header

Up until now the EBML Header length field has been written with eight
bytes, although the EBML Header is always so small that only one byte
is needed for it. This patch saves seven bytes for every Matroska/Webm
file.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

10 files changed, 40 insertions, 37 deletions

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 0448253..5e2127d 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -164,6 +164,9 @@ typedef struct MatroskaMuxContext {
     int allow_raw_vfw;
 } MatroskaMuxContext;
 
+/** 2 bytes * 7 for EBML IDs, 7 1-byte EBML lengths, 6 1-byte uint,
+ * 8 byte for "matroska" doctype string */
+#define MAX_EBML_HEADER_SIZE 35
 
 /** 2 bytes * 3 for EBML IDs, 3 1-byte EBML lengths, 8 bytes for 64 bit
  * offset, 4 bytes for target EBML ID */
@@ -1886,7 +1889,7 @@ static int mkv_write_header(AVFormatContext *s)
         ret = AVERROR(ENOMEM);
         goto fail;
     }
-    ebml_header = start_ebml_master(pb, EBML_ID_HEADER, 0);
+    ebml_header = start_ebml_master(pb, EBML_ID_HEADER, MAX_EBML_HEADER_SIZE);
     put_ebml_uint   (pb, EBML_ID_EBMLVERSION        ,           1);
     put_ebml_uint   (pb, EBML_ID_EBMLREADVERSION    ,           1);
     put_ebml_uint   (pb, EBML_ID_EBMLMAXIDLENGTH    ,           4);
diff --git a/tests/fate/matroska.mak b/tests/fate/matroska.mak
index 2747496..6bcd2b0 100644
--- a/tests/fate/matroska.mak
+++ b/tests/fate/matroska.mak
@@ -4,7 +4,7 @@
 FATE_MATROSKA-$(call DEMMUX, MATROSKA, MATROSKA) += fate-matroska-remux
 fate-matroska-remux: CMD = md5pipe -i $(TARGET_SAMPLES)/vp9-test-vectors/vp90-2-2pass-akiyo.webm -color_trc 4 -c:v copy -fflags +bitexact -strict -2 -f matroska
 fate-matroska-remux: CMP = oneline
-fate-matroska-remux: REF = 1ed49a4f2b6790357fac268938357353
+fate-matroska-remux: REF = 768af2b49132a0de5e0502926ab9ca4f
 
 FATE_MATROSKA_FFPROBE-$(call ALLYES, MATROSKA_DEMUXER) += fate-matroska-spherical-mono
 fate-matroska-spherical-mono: CMD = run ffprobe$(PROGSSUF)$(EXESUF) -show_entries stream_side_data_list -select_streams v -v 0 $(TARGET_SAMPLES)/mkv/spherical.mkv
diff --git a/tests/fate/wavpack.mak b/tests/fate/wavpack.mak
index e4e8d47..a4095a9 100644
--- a/tests/fate/wavpack.mak
+++ b/tests/fate/wavpack.mak
@@ -91,12 +91,12 @@ fate-wavpack-matroskamode: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/special/matros
 FATE_WAVPACK-$(call DEMMUX, WV, MATROSKA) += fate-wavpack-matroska_mux-mono
 fate-wavpack-matroska_mux-mono: CMD = md5pipe -i $(TARGET_SAMPLES)/wavpack/num_channels/mono_16bit_int.wv -c copy -fflags +bitexact -f matroska
 fate-wavpack-matroska_mux-mono: CMP = oneline
-fate-wavpack-matroska_mux-mono: REF = 11773e2a518edc788475f3880d849230
+fate-wavpack-matroska_mux-mono: REF = 646c726a80857b74a55ba16a6d83aeed
 
 FATE_WAVPACK-$(call DEMMUX, WV, MATROSKA) += fate-wavpack-matroska_mux-61
 fate-wavpack-matroska_mux-61: CMD = md5pipe -i $(TARGET_SAMPLES)/wavpack/num_channels/eva_2.22_6.1_16bit-partial.wv -c copy -fflags +bitexact -f matroska
 fate-wavpack-matroska_mux-61: CMP = oneline
-fate-wavpack-matroska_mux-61: REF = 9641abdf596c10c2e21bd9b026d4bade
+fate-wavpack-matroska_mux-61: REF = 35b033bc75a0e18bbaabbaef38914837
 
 FATE_SAMPLES_AVCONV += $(FATE_WAVPACK-yes)
 fate-wavpack: $(FATE_WAVPACK-yes)
diff --git a/tests/ref/fate/aac-autobsf-adtstoasc b/tests/ref/fate/aac-autobsf-adtstoasc
index 9ca8e7e..3537e82 100644
--- a/tests/ref/fate/aac-autobsf-adtstoasc
+++ b/tests/ref/fate/aac-autobsf-adtstoasc
@@ -1,5 +1,5 @@
-b0375ba00bcbd55023a176255b8d4ba2 *tests/data/fate/aac-autobsf-adtstoasc.matroska
-6728 tests/data/fate/aac-autobsf-adtstoasc.matroska
+63292d538da403964777e17eb65deae7 *tests/data/fate/aac-autobsf-adtstoasc.matroska
+6721 tests/data/fate/aac-autobsf-adtstoasc.matroska
 #extradata 0:        2, 0x0030001c
 #tb 0: 1/1000
 #media_type 0: audio
diff --git a/tests/ref/fate/binsub-mksenc b/tests/ref/fate/binsub-mksenc
index f247d9d..2f70224 100644
--- a/tests/ref/fate/binsub-mksenc
+++ b/tests/ref/fate/binsub-mksenc
@@ -1 +1 @@
-f80f42e646fce972e73aa6d99dcfa470
+5d6f6f595b38d33424c186484f1c39ee
diff --git a/tests/ref/fate/rgb24-mkv b/tests/ref/fate/rgb24-mkv
index 9f0064b..4e91e6c 100644
--- a/tests/ref/fate/rgb24-mkv
+++ b/tests/ref/fate/rgb24-mkv
@@ -1,5 +1,5 @@
-d84d5a83971be9c2caa2f4c37bbbfefd *tests/data/fate/rgb24-mkv.matroska
-58343 tests/data/fate/rgb24-mkv.matroska
+a00bb0c1bc614872d2267ce9059ae3c7 *tests/data/fate/rgb24-mkv.matroska
+58336 tests/data/fate/rgb24-mkv.matroska
 #tb 0: 1/10
 #media_type 0: video
 #codec_id 0: rawvideo
diff --git a/tests/ref/lavf/mka b/tests/ref/lavf/mka
index 87f5ad8..785197f 100644
--- a/tests/ref/lavf/mka
+++ b/tests/ref/lavf/mka
@@ -1,3 +1,3 @@
-2d9722c0691e140237af0036e3a178b0 *tests/data/lavf/lavf.mka
-43684 tests/data/lavf/lavf.mka
+8b1992d17a836e07c1464dc1eb4595ac *tests/data/lavf/lavf.mka
+43677 tests/data/lavf/lavf.mka
 tests/data/lavf/lavf.mka CRC=0x3a1da17e
diff --git a/tests/ref/lavf/mkv b/tests/ref/lavf/mkv
index 79f80f6..97c314c 100644
--- a/tests/ref/lavf/mkv
+++ b/tests/ref/lavf/mkv
@@ -1,3 +1,3 @@
-9767a3b526d7e56d7400164cb888990c *tests/data/lavf/lavf.mkv
-320603 tests/data/lavf/lavf.mkv
+c6d8a608b7d90820812962972926ef25 *tests/data/lavf/lavf.mkv
+320596 tests/data/lavf/lavf.mkv
 tests/data/lavf/lavf.mkv CRC=0xec6c3c68
diff --git a/tests/ref/lavf/mkv_attachment b/tests/ref/lavf/mkv_attachment
index 455a29f..cb5dd96 100644
--- a/tests/ref/lavf/mkv_attachment
+++ b/tests/ref/lavf/mkv_attachment
@@ -1,3 +1,3 @@
-7c8697c324e8ad79c5ea14364a6c39b8 *tests/data/lavf/lavf.mkv_attachment
-472759 tests/data/lavf/lavf.mkv_attachment
+27cb59473419ffb0b24fa1737ddcd6c7 *tests/data/lavf/lavf.mkv_attachment
+472752 tests/data/lavf/lavf.mkv_attachment
 tests/data/lavf/lavf.mkv_attachment CRC=0xec6c3c68
diff --git a/tests/ref/seek/lavf-mkv b/tests/ref/seek/lavf-mkv
index cea34e9..e2a0364 100644
--- a/tests/ref/seek/lavf-mkv
+++ b/tests/ref/seek/lavf-mkv
@@ -1,48 +1,48 @@
-ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    834 size:   208
+ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    827 size:   208
 ret: 0         st:-1 flags:0  ts:-1.000000
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret: 0         st:-1 flags:1  ts: 1.894167
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret: 0         st: 0 flags:0  ts: 0.788000
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret: 0         st: 0 flags:1  ts:-0.317000
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret:-1         st: 1 flags:0  ts: 2.577000
 ret: 0         st: 1 flags:1  ts: 1.471000
-ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320317 size:   209
+ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320310 size:   209
 ret: 0         st:-1 flags:0  ts: 0.365002
-ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147023 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147016 size: 27925
 ret: 0         st:-1 flags:1  ts:-0.740831
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret:-1         st: 0 flags:0  ts: 2.153000
 ret: 0         st: 0 flags:1  ts: 1.048000
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret: 0         st: 1 flags:0  ts:-0.058000
-ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    834 size:   208
+ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    827 size:   208
 ret: 0         st: 1 flags:1  ts: 2.836000
-ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320317 size:   209
+ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320310 size:   209
 ret:-1         st:-1 flags:0  ts: 1.730004
 ret: 0         st:-1 flags:1  ts: 0.624171
-ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147023 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147016 size: 27925
 ret: 0         st: 0 flags:0  ts:-0.482000
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret: 0         st: 0 flags:1  ts: 2.413000
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret:-1         st: 1 flags:0  ts: 1.307000
 ret: 0         st: 1 flags:1  ts: 0.201000
-ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    834 size:   208
+ret: 0         st: 1 flags:1 dts: 0.000000 pts: 0.000000 pos:    827 size:   208
 ret: 0         st:-1 flags:0  ts:-0.904994
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret: 0         st:-1 flags:1  ts: 1.989173
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret: 0         st: 0 flags:0  ts: 0.883000
-ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292476 size: 27834
+ret: 0         st: 0 flags:1 dts: 0.971000 pts: 0.971000 pos: 292469 size: 27834
 ret: 0         st: 0 flags:1  ts:-0.222000
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837
 ret:-1         st: 1 flags:0  ts: 2.672000
 ret: 0         st: 1 flags:1  ts: 1.566000
-ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320317 size:   209
+ret: 0         st: 1 flags:1 dts: 0.993000 pts: 0.993000 pos: 320310 size:   209
 ret: 0         st:-1 flags:0  ts: 0.460008
-ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147023 size: 27925
+ret: 0         st: 0 flags:1 dts: 0.491000 pts: 0.491000 pos: 147016 size: 27925
 ret: 0         st:-1 flags:1  ts:-0.645825
-ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1050 size: 27837
+ret: 0         st: 0 flags:1 dts: 0.011000 pts: 0.011000 pos:   1043 size: 27837