move mp3_header_compress bitstream filter in its own file

Originally committed as revision 9063 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 86 insertions, 0 deletions

diff --git a/libavcodec/mp3_header_compress_bsf.c b/libavcodec/mp3_header_compress_bsf.c
new file mode 100644
index 0000000000..f5c513834a
--- /dev/null
+++ b/libavcodec/mp3_header_compress_bsf.c
@@ -0,0 +1,86 @@
+/*
+ * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "mpegaudio.h"
+
+
+static int mp3_header_compress(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
+                     uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size, int keyframe){
+    uint32_t header, extraheader;
+    int mode_extension, header_size;
+
+    if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){
+        av_log(avctx, AV_LOG_ERROR, "not standards compliant\n");
+        return -1;
+    }
+
+    header = AV_RB32(buf);
+    mode_extension= (header>>4)&3;
+
+    if(ff_mpa_check_header(header) < 0 || (header&0x60000) != 0x20000){
+output_unchanged:
+        *poutbuf= (uint8_t *) buf;
+        *poutbuf_size= buf_size;
+
+        av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header);
+        return 0;
+    }
+
+    if(avctx->extradata_size == 0){
+        avctx->extradata_size=15;
+        avctx->extradata= av_malloc(avctx->extradata_size);
+        strcpy(avctx->extradata, "FFCMP3 0.0");
+        memcpy(avctx->extradata+11, buf, 4);
+    }
+    if(avctx->extradata_size != 15){
+        av_log(avctx, AV_LOG_ERROR, "Extradata invalid\n");
+        return -1;
+    }
+    extraheader = AV_RB32(avctx->extradata+11);
+    if((extraheader&MP3_MASK) != (header&MP3_MASK))
+        goto output_unchanged;
+
+    header_size= (header&0x10000) ? 4 : 6;
+
+    *poutbuf_size= buf_size - header_size;
+    *poutbuf= av_malloc(buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
+    memcpy(*poutbuf, buf + header_size, buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
+
+    if(avctx->channels==2){
+        if((header & (3<<19)) != 3<<19){
+            (*poutbuf)[1] &= 0x3F;
+            (*poutbuf)[1] |= mode_extension<<6;
+            FFSWAP(int, (*poutbuf)[1], (*poutbuf)[2]);
+        }else{
+            (*poutbuf)[1] &= 0x8F;
+            (*poutbuf)[1] |= mode_extension<<4;
+        }
+    }
+
+    return 1;
+}
+
+AVBitStreamFilter mp3_header_compress_bsf={
+    "mp3comp",
+    0,
+    mp3_header_compress,
+};