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Divide first audio buffer chunk into atomary bufffers. 

This slightly simplifies decoder and removes potential
audio buffer overrun.

Originally committed as revision 7121 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Kostya Shishkov 2006-11-19 05:30:43 +00:00
parent 5836d158b6
commit c8f9f9b91a
2 changed files with 37 additions and 22 deletions
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22
libavcodec/vmdav.c
View File

@ -519,12 +519,10 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx,
uint8_t *buf, int buf_size)
{
VmdAudioContext *s = (VmdAudioContext *)avctx->priv_data;
unsigned int sound_flags;
unsigned char *output_samples = (unsigned char *)data;
/* point to the start of the encoded data */
unsigned char *p = buf + 16;
unsigned char *p_end = buf + buf_size;
if (buf_size < 16)
return buf_size;
@ -533,24 +531,10 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx,
/* the chunk contains audio */
*data_size = vmdaudio_loadsound(s, output_samples, p, 0);
} else if (buf[6] == 2) {
/* the chunk contains audio and silence mixed together */
sound_flags = LE_32(p);
/* the chunk may contain audio */
p += 4;
/* do something with extrabufs here? */
while (p < p_end) {
if (sound_flags & 0x01)
/* silence */
*data_size += vmdaudio_loadsound(s, output_samples, p, 1);
else {
/* audio */
*data_size += vmdaudio_loadsound(s, output_samples, p, 0);
p += s->block_align;
}
output_samples += (s->block_align * s->bits / 8);
sound_flags >>= 1;
}
*data_size = vmdaudio_loadsound(s, output_samples, p, (buf_size == 16));
output_samples += (s->block_align * s->bits / 8);
} else if (buf[6] == 3) {
/* silent chunk */
*data_size = vmdaudio_loadsound(s, output_samples, p, 1);

37
libavformat/sierravmd.c
View File

@ -87,6 +87,7 @@ static int vmd_read_header(AVFormatContext *s,
int64_t current_video_pts = 0, current_audio_pts = 0;
unsigned char chunk[BYTES_PER_FRAME_RECORD];
int num, den;
int sound_buffers;
/* fetch the main header, including the 2 header length bytes */
url_fseek(pb, 0, SEEK_SET);
@ -146,13 +147,14 @@ static int vmd_read_header(AVFormatContext *s,
raw_frame_table = NULL;
vmd->frame_table = NULL;
sound_buffers = LE_16(&vmd->vmd_header[808]);
raw_frame_table_size = vmd->frame_count * 6;
raw_frame_table = av_malloc(raw_frame_table_size);
if(vmd->frame_count * vmd->frames_per_block >= UINT_MAX / sizeof(vmd_frame_t)){
av_log(s, AV_LOG_ERROR, "vmd->frame_count * vmd->frames_per_block too large\n");
return -1;
}
vmd->frame_table = av_malloc(vmd->frame_count * vmd->frames_per_block * sizeof(vmd_frame_t));
vmd->frame_table = av_malloc((vmd->frame_count * vmd->frames_per_block + sound_buffers) * sizeof(vmd_frame_t));
if (!raw_frame_table || !vmd->frame_table) {
av_free(raw_frame_table);
av_free(vmd->frame_table);
@ -182,14 +184,43 @@ static int vmd_read_header(AVFormatContext *s,
continue;
switch(type) {
case 1: /* Audio Chunk */
/* first audio chunk contains several audio buffers */
if(current_audio_pts){
vmd->frame_table[total_frames].frame_offset = current_offset;
vmd->frame_table[total_frames].stream_index = vmd->audio_stream_index;
vmd->frame_table[total_frames].frame_size = size;
memcpy(vmd->frame_table[total_frames].frame_record, chunk, BYTES_PER_FRAME_RECORD);
vmd->frame_table[total_frames].pts = current_audio_pts;
total_frames++;
/* first audio chunk contains several audio buffers */
current_audio_pts += (current_audio_pts == 0) ? LE_16(&vmd->vmd_header[808]) * pts_inc : pts_inc;
current_audio_pts += pts_inc;
}else{
uint32_t flags;
int k;
int noff;
int64_t pos;
pos = url_ftell(pb);
url_fseek(pb, current_offset, SEEK_SET);
flags = get_le32(pb);
noff = 4;
url_fseek(pb, pos, SEEK_SET);
av_log(s, AV_LOG_DEBUG, "Sound mapping = %08X (%i bufs)\n", flags, sound_buffers);
for(k = 0; k < sound_buffers - 1; k++){
if(flags & 1) { /* silent block */
vmd->frame_table[total_frames].frame_size = 0;
}else{
vmd->frame_table[total_frames].frame_size = st->codec->block_align + (st->codec->block_align & 1);
}
noff += vmd->frame_table[total_frames].frame_size;
vmd->frame_table[total_frames].frame_offset = current_offset + noff;
vmd->frame_table[total_frames].stream_index = vmd->audio_stream_index;
memcpy(vmd->frame_table[total_frames].frame_record, chunk, BYTES_PER_FRAME_RECORD);
vmd->frame_table[total_frames].pts = current_audio_pts;
total_frames++;
current_audio_pts += pts_inc;
flags >>= 1;
}
}
break;
case 2: /* Video Chunk */
vmd->frame_table[total_frames].frame_offset = current_offset;