[FFmpeg-devel] [PATCH] ffmpeg.c: Strip off ADTS Header from AAC audio as it is needed only in TS and not needed in 3GP, MP4, FLV, ISM formats

[Chiranjeevi Melam]

Hi,
As per feedback, moved this feature to ffmpeg/libavcodec/aac_adtstoasc_bsf.c file and created a new function " SkipADTSHeader" in the file ffmpeg/libavcodec/aac_adtstoasc_bsf.c.
Thanks,
Chiru


diff --git a/ffmpeg/ffmpeg_orig.c b/ffmpeg/ffmpeg.c
index 95b3252..d44a09f 100755
--- a/ffmpeg/ffmpeg_orig.c
+++ b/ffmpeg/ffmpeg.c
@@ -1828,6 +1828,12 @@ static int output_packet(InputStream *ist, int ist_index,
                             opkt.size = data_size;
                         }

+                                               if(ost->st->codec->codec_id == CODEC_ID_AAC) {
+                            if(!strcmp(input_files[ist->file_index]->iformat->name, "mpegts") && strcmp(output_files[ost->file_index]->oformat->name, "mpegts") ) {
+                                                               SkipADTSHeader(&opkt, data_size, audio_size);
+                                                       }
+                                               }
+
                         if (os->oformat->flags & AVFMT_RAWPICTURE) {
                             /* store AVPicture in AVPacket, as expected by the output format */
                             avpicture_fill(&pict, opkt.data, ost->st->codec->pix_fmt, ost->st->codec->width, ost->st->codec->height);



diff --git a/ffmpeg/libavcodec/aac_adtstoasc_bsf_orig.c b/ffmpeg/libavcodec/aac_adtstoasc_bsf.c
index 6558c02..cb5cc61 100755
--- a/ffmpeg/libavcodec/aac_adtstoasc_bsf_orig.c
+++ b/ffmpeg/libavcodec/aac_adtstoasc_bsf.c
@@ -26,6 +26,8 @@
 #include "mpeg4audio.h"
 #include "internal.h"

+int SkipADTSHeader(AVPacket *o_pkt, int dsize, int asize);
+
 typedef struct AACBSFContext {
     int first_frame_done;
 } AACBSFContext;
@@ -107,6 +109,21 @@ static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc,
     return 0;
 }

+int SkipADTSHeader(AVPacket *o_pkt, int datasize, int audiosize)
+{
+       int32_t offset = 7;
+               if(o_pkt->data[0] == 0xff && (o_pkt->data[1] & 0xf0) == 0xf0) {
+                       // skip ADTS CRC
+            if((o_pkt->data[1] & 0x1) == 0x00)
+                               offset += 2;
+            o_pkt->data  += offset;
+            o_pkt->size  -= offset;
+            datasize  -= offset;
+            audiosize -= offset;
+               }
+       return 0;
+}
+
 AVBitStreamFilter ff_aac_adtstoasc_bsf = {
     "aac_adtstoasc",
     sizeof(AACBSFContext),


-----Original Message-----
From: ffmpeg-devel-bounces at ffmpeg.org [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of Michael Niedermayer
Sent: Wednesday, August 24, 2011 2:07 PM
To: FFmpeg development discussions and patches
Subject: Re: [FFmpeg-devel] [PATCH] ffmpeg.c: Strip off ADTS Header from AAC audio as it is needed only in TS and not needed in 3GP, MP4, FLV, ISM formats

On Wed, Aug 24, 2011 at 05:04:21PM +0000, Chiranjeevi Melam wrote:
> All,
> The patch is to strip off ADTS Header from AAC audio as it is needed only in TS and not needed in 3GP, MP4, FLV, ISM formats.
> Thanks,
> Chiru

Please see:
"[PATCH]AAC audio: Skip ADTS Header when copied from TS container to Non-TS containers"

for review and comments

I am not against the patch if there is a problem with doing it with a bitstream filter or in the muxer, but if there is, iam not aware of it

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship naturally arises out of democracy, and the most aggravated form of tyranny and slavery out of the most extreme liberty. -- Plato