avienc: sanitize variable naming in write_header()

Do not call an AVCodecContext 'stream', that is highly confusing.
Also, add a local variable for the current AVStream in the loop over all
streams.

libavformat/avienc.c

@@ -143,7 +143,7 @@ static int avi_write_header(AVFormatContext *s)
     AVIContext *avi = s->priv_data;
     AVIOContext *pb = s->pb;
     int bitrate, n, i, nb_frames, au_byterate, au_ssize, au_scale;
-    AVCodecContext *stream, *video_enc;
+    AVCodecContext *video_enc;
     int64_t list1, list2, strh, strf;
     AVDictionaryEntry *t = NULL;
 
@@ -170,10 +170,10 @@ static int avi_write_header(AVFormatContext *s)
 
     video_enc = NULL;
     for (n = 0; n < s->nb_streams; n++) {
-        stream   = s->streams[n]->codec;
-        bitrate += stream->bit_rate;
-        if (stream->codec_type == AVMEDIA_TYPE_VIDEO)
-            video_enc = stream;
+        AVCodecContext *codec = s->streams[n]->codec;
+        bitrate += codec->bit_rate;
+        if (codec->codec_type == AVMEDIA_TYPE_VIDEO)
+            video_enc = codec;
     }
 
     nb_frames = 0;
@@ -208,19 +208,19 @@ static int avi_write_header(AVFormatContext *s)
 
     /* stream list */
     for (i = 0; i < n; i++) {
-        AVIStream *avist = s->streams[i]->priv_data;
+        AVStream *st = s->streams[i];
+        AVCodecContext *enc = st->codec;
+        AVIStream *avist = st->priv_data;
         list2 = ff_start_tag(pb, "LIST");
         ffio_wfourcc(pb, "strl");
 
-        stream = s->streams[i]->codec;
-
         /* stream generic header */
         strh = ff_start_tag(pb, "strh");
-        switch (stream->codec_type) {
+        switch (enc->codec_type) {
         case AVMEDIA_TYPE_SUBTITLE:
             // XSUB subtitles behave like video tracks, other subtitles
             // are not (yet) supported.
-            if (stream->codec_id != AV_CODEC_ID_XSUB) {
+            if (enc->codec_id != AV_CODEC_ID_XSUB) {
                 av_log(s, AV_LOG_ERROR,
                        "Subtitle streams other than DivX XSUB are not supported by the AVI muxer.\n");
                 return AVERROR_PATCHWELCOME;
@@ -238,9 +238,9 @@ static int avi_write_header(AVFormatContext *s)
             ffio_wfourcc(pb, "dats");
             break;
         }
-        if (stream->codec_type == AVMEDIA_TYPE_VIDEO ||
-            stream->codec_id == AV_CODEC_ID_XSUB)
-            avio_wl32(pb, stream->codec_tag);
+        if (enc->codec_type == AVMEDIA_TYPE_VIDEO ||
+            enc->codec_id == AV_CODEC_ID_XSUB)
+            avio_wl32(pb, enc->codec_tag);
         else
             avio_wl32(pb, 1);
         avio_wl32(pb, 0); /* flags */
@@ -248,11 +248,11 @@ static int avi_write_header(AVFormatContext *s)
         avio_wl16(pb, 0); /* language */
         avio_wl32(pb, 0); /* initial frame */
 
-        ff_parse_specific_params(stream, &au_byterate, &au_ssize, &au_scale);
+        ff_parse_specific_params(enc, &au_byterate, &au_ssize, &au_scale);
 
         avio_wl32(pb, au_scale); /* scale */
         avio_wl32(pb, au_byterate); /* rate */
-        avpriv_set_pts_info(s->streams[i], 64, au_scale, au_byterate);
+        avpriv_set_pts_info(st, 64, au_scale, au_byterate);
 
         avio_wl32(pb, 0); /* start */
         /* remember this offset to fill later */
@@ -264,39 +264,39 @@ static int avi_write_header(AVFormatContext *s)
             avio_wl32(pb, 0);  /* length, XXX: filled later */
 
         /* suggested buffer size */ //FIXME set at the end to largest chunk
-        if (stream->codec_type == AVMEDIA_TYPE_VIDEO)
+        if (enc->codec_type == AVMEDIA_TYPE_VIDEO)
             avio_wl32(pb, 1024 * 1024);
-        else if (stream->codec_type == AVMEDIA_TYPE_AUDIO)
+        else if (enc->codec_type == AVMEDIA_TYPE_AUDIO)
             avio_wl32(pb, 12 * 1024);
         else
             avio_wl32(pb, 0);
         avio_wl32(pb, -1); /* quality */
         avio_wl32(pb, au_ssize); /* sample size */
         avio_wl32(pb, 0);
-        avio_wl16(pb, stream->width);
-        avio_wl16(pb, stream->height);
+        avio_wl16(pb, enc->width);
+        avio_wl16(pb, enc->height);
         ff_end_tag(pb, strh);
 
-        if (stream->codec_type != AVMEDIA_TYPE_DATA) {
+        if (enc->codec_type != AVMEDIA_TYPE_DATA) {
             strf = ff_start_tag(pb, "strf");
-            switch (stream->codec_type) {
+            switch (enc->codec_type) {
             case AVMEDIA_TYPE_SUBTITLE:
                 /* XSUB subtitles behave like video tracks, other subtitles
                  * are not (yet) supported. */
-                if (stream->codec_id != AV_CODEC_ID_XSUB)
+                if (enc->codec_id != AV_CODEC_ID_XSUB)
                     break;
             case AVMEDIA_TYPE_VIDEO:
-                ff_put_bmp_header(pb, stream, ff_codec_bmp_tags, 0);
+                ff_put_bmp_header(pb, enc, ff_codec_bmp_tags, 0);
                 break;
             case AVMEDIA_TYPE_AUDIO:
-                if (ff_put_wav_header(pb, stream) < 0)
+                if (ff_put_wav_header(pb, enc) < 0)
                     return -1;
                 break;
             default:
                 return -1;
             }
             ff_end_tag(pb, strf);
-            if ((t = av_dict_get(s->streams[i]->metadata, "title", NULL, 0))) {
+            if ((t = av_dict_get(st->metadata, "title", NULL, 0))) {
                 ff_riff_write_info_tag(s->pb, "strn", t->value);
                 t = NULL;
             }
@@ -316,7 +316,7 @@ static int avi_write_header(AVFormatContext *s)
             avio_w8(pb, 0);     /* bIndexSubType (0 == frame index) */
             avio_w8(pb, 0);     /* bIndexType (0 == AVI_INDEX_OF_INDEXES) */
             avio_wl32(pb, 0);   /* nEntriesInUse (will fill out later on) */
-            ffio_wfourcc(pb, avi_stream2fourcc(tag, i, stream->codec_type));
+            ffio_wfourcc(pb, avi_stream2fourcc(tag, i, enc->codec_type));
                                 /* dwChunkId */
             avio_wl64(pb, 0);   /* dwReserved[3] */
             // avio_wl32(pb, 0);   /* Must be 0.    */
@@ -325,31 +325,31 @@ static int avi_write_header(AVFormatContext *s)
             ff_end_tag(pb, avist->indexes.indx_start);
         }
 
-        if (stream->codec_type == AVMEDIA_TYPE_VIDEO   &&
-            s->streams[i]->sample_aspect_ratio.num > 0 &&
-            s->streams[i]->sample_aspect_ratio.den > 0) {
+        if (enc->codec_type == AVMEDIA_TYPE_VIDEO   &&
+            st->sample_aspect_ratio.num > 0 &&
+            st->sample_aspect_ratio.den > 0) {
             int vprp       = ff_start_tag(pb, "vprp");
-            AVRational dar = av_mul_q(s->streams[i]->sample_aspect_ratio,
-                                      (AVRational) { stream->width,
-                                                     stream->height });
+            AVRational dar = av_mul_q(st->sample_aspect_ratio,
+                                      (AVRational) { enc->width,
+                                                     enc->height });
             int num, den;
             av_reduce(&num, &den, dar.num, dar.den, 0xFFFF);
 
             avio_wl32(pb, 0); // video format   = unknown
             avio_wl32(pb, 0); // video standard = unknown
-            avio_wl32(pb, lrintf(1.0 / av_q2d(stream->time_base)));
-            avio_wl32(pb, stream->width);
-            avio_wl32(pb, stream->height);
+            avio_wl32(pb, lrintf(1.0 / av_q2d(enc->time_base)));
+            avio_wl32(pb, enc->width);
+            avio_wl32(pb, enc->height);
             avio_wl16(pb, den);
             avio_wl16(pb, num);
-            avio_wl32(pb, stream->width);
-            avio_wl32(pb, stream->height);
+            avio_wl32(pb, enc->width);
+            avio_wl32(pb, enc->height);
             avio_wl32(pb, 1); // progressive FIXME
 
-            avio_wl32(pb, stream->height);
-            avio_wl32(pb, stream->width);
-            avio_wl32(pb, stream->height);
-            avio_wl32(pb, stream->width);
+            avio_wl32(pb, enc->height);
+            avio_wl32(pb, enc->width);
+            avio_wl32(pb, enc->height);
+            avio_wl32(pb, enc->width);
             avio_wl32(pb, 0);
             avio_wl32(pb, 0);